Merge branch 'zxw/dev_mac_update_engine' into siyaoH/1.17/windows

Samples/UIWidgetsSamples_2019_4/Assets/Editor/EditorWindowSample/GalleryMain.cs

+using System.Collections.Generic;
+using Unity.UIWidgets.engine2;
+using Unity.UIWidgets.widgets;
-using ui_ = Unity.UIWidgets.widgets.ui_;
+using UnityEngine;
+
-        
+
+        protected override void onEnable()
+        {
+            AddFont("Material Icons", new List<string> {"MaterialIcons-Regular.ttf"}, new List<int> {0});
+            AddFont("CupertinoIcons", new List<string> {"CupertinoIcons.ttf"}, new List<int> {0});
+            AddFont("GalleryIcons", new List<string> {"gallery/GalleryIcons.ttf"}, new List<int> {0});
+        }
+
         protected override void main()
         {
             ui_.runApp(new GalleryApp());

Samples/UIWidgetsSamples_2019_4/Assets/Script/TextTest.cs

 using Brightness = Unity.UIWidgets.ui.Brightness;
 using UnityEngine;
 using System;
+using uiwidgets;
+using Unity.UIWidgets.gestures;
+using Unity.UIWidgets.material;
+using UnityEngine.Networking;
+using Transform = Unity.UIWidgets.widgets.Transform;
 
 namespace UIWidgetsSample
 {
         {
             ui_.runApp(new MyApp());
         }
+        class MyApp : StatelessWidget {
+          public override Widget build(BuildContext context) {
+            return new MaterialApp(
+              debugShowCheckedModeBanner: false,
+              title: "Flutter Demo",
+              home: new Scaffold(
+                appBar: new AppBar(title: new Text("good")),
+                body: new Center(
+                    child: new MyStatefulWidget()
+                  )
+                )
+            );
+          }
+        } 
+        class MyStatefulWidget : StatefulWidget {
+          public MyStatefulWidget(Key key = null) : base(key: key)
+          {
+          }
-        class MyApp : StatelessWidget
-        {
-            public override Widget build(BuildContext context)
-            {
-                return new CupertinoApp(
-                    home: new HomeScreen() //new DetailScreen1("ok")
-                    //color: Color.white
-                );
-            }
+          public override State createState() => new _MyStatefulWidgetState();
+
+        class _MyStatefulWidgetState : State<MyStatefulWidget> {
+          Color textColor = Colors.blue;
+          int _enterCounter = 0;
+          int _exitCounter = 0;
+          float x = 0.0f;
+          float y = 0.0f;
+
+          void _incrementEnter(PointerEvent details) {
+              UnityEngine.Debug.Log("enter");
+            setState(() =>{
+                
+              _enterCounter++;
+            });
+          }
+
+          void _incrementExit(PointerEvent details) {
+            setState(() =>{
+              textColor = Colors.blue;
+              _exitCounter++;
+            });
+          }
+
+          void _updateLocation(PointerEvent details) {
+            setState(() =>{
+              textColor = Colors.red;
+              x = details.position.dx;
+              y = details.position.dy;
+            });
+          }
+
+
+          public override Widget build(BuildContext context) {
+              return new MouseRegion(
+              onEnter: _incrementEnter,
+              onHover: _updateLocation,
+              onExit: _incrementExit,
+              child: new FlatButton(
+                color: Colors.white,
+                textColor: Colors.teal[700], //when hovered text color change
+                shape: new RoundedRectangleBorder(
+                  borderRadius: BorderRadius.circular(5),
+                  side: new BorderSide(
+                    color: Colors.teal[700]
+                  )
+                ),
+                onPressed: () => { },
+                child: new Text("Log in", style: new TextStyle(color: textColor))
+              )
+            );
+          }
+        }
+    
+        
+
 
         class HomeScreen : StatelessWidget
         {

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/GalleryMain.cs

+using System.Collections.Generic;
-using ui_ = Unity.UIWidgets.widgets.ui_;
+using Unity.UIWidgets.widgets;
-namespace UIWidgetsGallery {
-    public class GalleryMain : UIWidgetsPanel {
-        protected override void main() {
+namespace UIWidgetsGallery
+{
+    public class GalleryMain : UIWidgetsPanel
+    {
+        protected new void OnEnable()
+        {
+            base.OnEnable();
+        }
+
+        protected override void main()
+        {
-        protected new void OnEnable() {
-            base.OnEnable();
+        protected override void onEnable()
+        {
+            AddFont("Material Icons", new List<string> {"MaterialIcons-Regular.ttf"}, new List<int> {0});
+            AddFont("CupertinoIcons", new List<string> {"CupertinoIcons.ttf"}, new List<int> {0});
+            AddFont("GalleryIcons", new List<string> {"gallery/GalleryIcons.ttf"}, new List<int> {0});
-}
+}

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/material/bottom_app_bar_demo.cs

 
     internal class _BottomAppBarDemoState : State<BottomAppBarDemo>
     {
-        private static GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>.key();
+        private static readonly GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>.key();
 
         // FAB shape
 
                 value: FloatingActionButtonLocation.centerFloat
             );
 
-        private static void _showSnackbar()
-        {
-            string text =
-                "When the Scaffold\"s floating action button location changes, " +
-                "the floating action button animates to its new position. " +
-                "The BottomAppBar adapts its shape appropriately.";
-
-            _scaffoldKey.currentState.showSnackBar(
-                new SnackBar(content: new Text(text))
-            );
-        }
-
-        private static List<_NamedColor> kBabColors = new List<_NamedColor>
+        private static readonly List<_NamedColor> kBabColors = new List<_NamedColor>
         {
             new _NamedColor(null, "Clear"),
             new _NamedColor(new Color(0xFFFFC100), "Orange"),
-            new _NamedColor(new Color(0xFF009BEE), "Blue"),
+            new _NamedColor(new Color(0xFF009BEE), "Blue")
+        private Color _babColor = kBabColors.First().color;
+        private _ChoiceValue<FloatingActionButtonLocation> _fabLocation = kFabEndDocked;
+
-        private _ChoiceValue<FloatingActionButtonLocation> _fabLocation = kFabEndDocked;
-        private Color _babColor = kBabColors.First().color;
+
+        private static void _showSnackbar()
+        {
+            var text =
+                "When the Scaffold\"s floating action button location changes, " +
+                "the floating action button animates to its new position. " +
+                "The BottomAppBar adapts its shape appropriately.";
+
+            _scaffoldKey.currentState.showSnackBar(
+                new SnackBar(content: new Text(text))
+            );
+        }
-            this.setState(() => { this._showNotch = value; });
+            setState(() => { _showNotch = value; });
-            this.setState(() => { this._fabShape = value; });
+            setState(() => { _fabShape = value; });
-            this.setState(() => { this._fabLocation = value; });
+            setState(() => { _fabLocation = value; });
-            this.setState(() => { this._babColor = value; });
+            setState(() => { _babColor = value; });
-                key: _scaffoldKey,
-                appBar: new AppBar(
+                _scaffoldKey,
+                new AppBar(
                     title: new Text("Bottom app bar"),
                     elevation: 0.0f,
                     actions: new List<Widget>
                             icon: new Icon(Icons.sentiment_very_satisfied),
                             onPressed: () =>
                             {
-                                this.setState(() =>
-                                {
-                                    this._fabShape = this._fabShape == kCircularFab ? kDiamondFab : kCircularFab;
-                                });
+                                setState(() => { _fabShape = _fabShape == kCircularFab ? kDiamondFab : kCircularFab; });
-                body: new Scrollbar(
+                new Scrollbar(
                     child: new ListView(
                         padding: EdgeInsets.only(bottom: 88.0f),
                         children: new List<Widget>
-                            new _RadioItem<Widget>(kCircularFab, this._fabShape, this._onFabShapeChanged),
-                            new _RadioItem<Widget>(kDiamondFab, this._fabShape, this._onFabShapeChanged),
-                            new _RadioItem<Widget>(kNoFab, this._fabShape, this._onFabShapeChanged),
+                            new _RadioItem<Widget>(kCircularFab, _fabShape, _onFabShapeChanged),
+                            new _RadioItem<Widget>(kDiamondFab, _fabShape, _onFabShapeChanged),
+                            new _RadioItem<Widget>(kNoFab, _fabShape, _onFabShapeChanged),
-                            new _RadioItem<bool>(kShowNotchTrue, this._showNotch, this._onShowNotchChanged),
-                            new _RadioItem<bool>(kShowNotchFalse, this._showNotch, this._onShowNotchChanged),
+                            new _RadioItem<bool>(kShowNotchTrue, _showNotch, _onShowNotchChanged),
+                            new _RadioItem<bool>(kShowNotchFalse, _showNotch, _onShowNotchChanged),
-                            new _RadioItem<FloatingActionButtonLocation>(kFabEndDocked, this._fabLocation,
-                                this._onFabLocationChanged),
-                            new _RadioItem<FloatingActionButtonLocation>(kFabCenterDocked, this._fabLocation,
-                                this._onFabLocationChanged),
-                            new _RadioItem<FloatingActionButtonLocation>(kFabEndFloat, this._fabLocation,
-                                this._onFabLocationChanged),
-                            new _RadioItem<FloatingActionButtonLocation>(kFabCenterFloat, this._fabLocation,
-                                this._onFabLocationChanged),
+                            new _RadioItem<FloatingActionButtonLocation>(kFabEndDocked, _fabLocation,
+                                _onFabLocationChanged),
+                            new _RadioItem<FloatingActionButtonLocation>(kFabCenterDocked, _fabLocation,
+                                _onFabLocationChanged),
+                            new _RadioItem<FloatingActionButtonLocation>(kFabEndFloat, _fabLocation,
+                                _onFabLocationChanged),
+                            new _RadioItem<FloatingActionButtonLocation>(kFabCenterFloat, _fabLocation,
+                                _onFabLocationChanged),
-                            new _ColorsItem(kBabColors, this._babColor, this._onBabColorChanged)
+                            new _ColorsItem(kBabColors, _babColor, _onBabColorChanged)
-                floatingActionButton: this._fabShape.value,
-                floatingActionButtonLocation: this._fabLocation.value,
+                _fabShape.value,
+                _fabLocation.value,
-                    color: this._babColor,
-                    fabLocation: this._fabLocation.value,
-                    shape: this._selectNotch()
+                    _babColor,
+                    _fabLocation.value,
+                    _selectNotch()
                 )
             );
         }
-            if (!this._showNotch.value)
+            if (!_showNotch.value)
-            if (this._fabShape == kCircularFab)
+            if (_fabShape == kCircularFab)
-            if (this._fabShape == kDiamondFab)
+            if (_fabShape == kDiamondFab)
                 return new _DiamondNotchedRectangle();
             return null;
         }
     {
+        public readonly string label; // For the Semantics widget that contains title
+        public readonly string title;
+
+        public readonly T value;
+
         public _ChoiceValue(T value, string title, string label)
         {
             this.value = value;
 
-        public readonly T value;
-        public readonly string title;
-        public readonly string label; // For the Semantics widget that contains title
-
-            return $"{this.GetType()}(\"{this.title}\")";
+            return $"{GetType()}(\"{title}\")";
+        public readonly _ChoiceValue<T> groupValue;
+        public readonly ValueChanged<_ChoiceValue<T>> onChanged;
+
+        public readonly _ChoiceValue<T> value;
+
         public _RadioItem(_ChoiceValue<T> value, _ChoiceValue<T> groupValue, ValueChanged<_ChoiceValue<T>> onChanged)
         {
             this.value = value;
 
-        public readonly _ChoiceValue<T> value;
-        public readonly _ChoiceValue<T> groupValue;
-        public readonly ValueChanged<_ChoiceValue<T>> onChanged;
-
-            ThemeData theme = Theme.of(context);
+            var theme = Theme.of(context);
-                //TODO: uncomment this when fixes on EdgeInsetsDirectional lands
-                //padding: const EdgeInsetsDirectional.only(start: 16.0),
-                padding: EdgeInsets.only(left: 16.0f),
+                padding: EdgeInsetsDirectional.only(16.0f),
-                            value: this.value,
-                            groupValue: this.groupValue,
-                            onChanged: this.onChanged
+                            value: value,
+                            groupValue: groupValue,
+                            onChanged: onChanged
-                                onTap: () =>
-                                {
-                                    this.onChanged(this.value);
-                                },
-                                child: new Text(this.value.title,
+                                onTap: () => { onChanged(value); },
+                                child: new Text(value.title,
                                     style: theme.textTheme.subtitle1
                                 )
                             )
 
     internal class _NamedColor
     {
+        public readonly Color color;
+        public readonly string name;
+
-
-        public readonly Color color;
-        public readonly string name;
+        public readonly List<_NamedColor> colors;
+        public readonly ValueChanged<Color> onChanged;
+        public readonly Color selectedColor;
+
         public _ColorsItem(List<_NamedColor> colors, Color selectedColor, ValueChanged<Color> onChanged)
         {
             this.colors = colors;
 
-        public readonly List<_NamedColor> colors;
-        public readonly Color selectedColor;
-        public readonly ValueChanged<Color> onChanged;
-
-                children: this.colors.Select<_NamedColor, Widget>((_NamedColor namedColor) =>
+                children: colors.Select<_NamedColor, Widget>(namedColor =>
-                        onPressed: () => { this.onChanged(namedColor.color); },
+                        onPressed: () => { onChanged(namedColor.color); },
-                            width: 32.0f,
-                            height: 32.0f
+                            32.0f,
+                            32.0f
-                            side: new BorderSide(
-                                color: namedColor.color == this.selectedColor ? Colors.black : new Color(0xFFD5D7DA),
-                                width: 2.0f
+                            new BorderSide(
+                                namedColor.color == selectedColor ? Colors.black : new Color(0xFFD5D7DA),
+                                2.0f
                             )
                         ),
                         child: new Container(
 
     internal class _Heading : StatelessWidget
     {
+        public readonly string text;
+
-
-        public readonly string text;
-            ThemeData theme = Theme.of(context);
+            var theme = Theme.of(context);
-                //TODO: uncomment this when fixes on EdgeInsetsDirectional lands
-                //padding:  EdgeInsetsDirectional.only(start: 56.0),
-                padding: EdgeInsets.only(left: 56.0f),
+                padding: EdgeInsetsDirectional.only(56.0f),
-                child: new Text(this.text,
+                child: new Text(text,
                     style: theme.textTheme.bodyText2.copyWith(
                         color: theme.primaryColor
                     )
 
     internal class _DemoBottomAppBar : StatelessWidget
     {
+        private static readonly List<FloatingActionButtonLocation> kCenterLocations =
+            new List<FloatingActionButtonLocation>
+            {
+                FloatingActionButtonLocation.centerDocked,
+                FloatingActionButtonLocation.centerFloat
+            };
+
+        public readonly Color color;
+        public readonly FloatingActionButtonLocation fabLocation;
+        public readonly NotchedShape shape;
+
         public _DemoBottomAppBar(
             Color color = null,
             FloatingActionButtonLocation fabLocation = null,
             this.shape = shape;
         }
 
-        public readonly Color color;
-        public readonly FloatingActionButtonLocation fabLocation;
-        public readonly NotchedShape shape;
-
-        private static readonly List<FloatingActionButtonLocation> kCenterLocations =
-            new List<FloatingActionButtonLocation>
-            {
-                FloatingActionButtonLocation.centerDocked,
-                FloatingActionButtonLocation.centerFloat
-            };
-
 
         public override Widget build(BuildContext context)
         {
                     onPressed: () =>
                     {
                         material_.showModalBottomSheet<object>(
-                            context: context,
-                            builder: (BuildContext subContext) => new _DemoDrawer()
+                            context,
+                            subContext => new _DemoDrawer()
-            if (kCenterLocations.Contains(this.fabLocation)) children.Add(new Expanded(child: new SizedBox()));
+            if (kCenterLocations.Contains(fabLocation)) children.Add(new Expanded(child: new SizedBox()));
 
             children.Add(
                 new IconButton(
 
 
             return new BottomAppBar(
-                color: this.color,
-                shape: this.shape,
+                color: color,
+                shape: shape,
                 child: new Row(children: children)
             );
         }
     {
-        public _DemoDrawer()
-        {
-        }
-
         public override Widget build(BuildContext context)
         {
             return new Drawer(
 
     internal class _DiamondFab : StatelessWidget
     {
+        public readonly Widget child;
+        public readonly VoidCallback onPressed;
+
         public _DiamondFab(
             Widget child = null,
             VoidCallback onPressed = null
             this.onPressed = onPressed;
         }
 
-        public readonly Widget child;
-        public readonly VoidCallback onPressed;
-
         public override Widget build(BuildContext context)
         {
             return new Material(
-                    onTap: () => this.onPressed?.Invoke(),
+                    onTap: () => onPressed?.Invoke(),
-                            data: new IconThemeData(color: Theme.of(context).accentIconTheme.color),
-                            child: this.child
+                            data: new IconThemeData(Theme.of(context).accentIconTheme.color),
+                            child: child
                         )
                     )
                 ),
 
     internal class _DiamondNotchedRectangle : NotchedShape
     {
-        public _DiamondNotchedRectangle()
-        {
-        }
-
         public override Path getOuterPath(Rect host, Rect guest)
         {
             //there is a bug in flutter when guest == null, we fix it here
 
             D.assert(guest.width > 0.0f);
 
-            Rect intersection = guest.intersect(host);
+            var intersection = guest.intersect(host);
             // We are computing a "V" shaped notch, as in this diagram:
             //    -----\****   /-----
             //          \     /
             //  notchToCenter is the horizontal distance between the guest's center and
             //  the host's top edge where the notch starts (marked with "*").
             //  We compute notchToCenter by similar triangles:
-            float notchToCenter =
+            var notchToCenter =
                 intersection.height * (guest.height / 2.0f)
                 / (guest.width / 2.0f);
 
 
     internal class _DiamondBorder : ShapeBorder
     {
-        public _DiamondBorder()
-        {
-        }
-
-            return this.getOuterPath(rect, textDirection: textDirection);
+            return getOuterPath(rect, textDirection);
         }
 
 

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/gallery/demos.cs

 using System.Linq;
 using UIWidgetsGallery.demo;
 using UIWidgetsGallery.demo.material;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.material;
 using Unity.UIWidgets.widgets;
 
             foreach (var category in kAllGalleryDemoCategories)
                 result.Add(category,
-                    kAllGalleryDemos.Where((GalleryDemo demo) => { return demo.category == category; }).ToList());
+                    LinqUtils<GalleryDemo>.WhereList(kAllGalleryDemos,((GalleryDemo demo) => { return demo.category == category; })));
 
             return result;
         }

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/ToDoAppSample.cs

 using Unity.UIWidgets.rendering;
 using Unity.UIWidgets.ui;
 using Unity.UIWidgets.widgets;
+using Unity.UIWidgets.external;
 using UnityEngine;
 using Color = Unity.UIWidgets.ui.Color;
 using TextStyle = Unity.UIWidgets.painting.TextStyle;
 
             Widget contents()
             {
-                var children = this.items.Select((item) =>
+                var children = LinqUtils<Widget,ToDoItem>.SelectList(this.items, (ToDoItem item) =>
                 {
                     return (Widget) new Text(
                         item.content, style: new TextStyle(

com.unity.uiwidgets/Editor/UIWidgetsEditorPanel.cs

 using System.Collections;
 using System.Collections.Generic;
-using Unity.UIWidgets.editor2;
+using Font = Unity.UIWidgets.engine2.Font;
-        UIWidgetsPanelWrapper _wrapper;
-        public UIWidgetsWindowType getWindowType() {
-            return UIWidgetsWindowType.EditorWindowPanel;
-        }
-        
-        public bool isActive() {
-            return true;
-        }
-
-        public void startCoroutine(IEnumerator routing) {
-            this.StartCoroutine(routing);
-        }
-        
-        public void onNewFrameScheduled() {
-            Repaint();
-        }
-
-        public Offset windowPosToScreenPos(Offset offset) {
-            return offset;
-        }
+        Configurations _configurations;
+        bool _ShowDebugLog;
+        UIWidgetsPanelWrapper _wrapper;
-            get { return Mathf.RoundToInt(position.size.x); }
+            get { return Mathf.RoundToInt(f: position.size.x); }
-            get { return Mathf.RoundToInt(position.size.y); }
+            get { return Mathf.RoundToInt(f: position.size.y); }
         }
 
         float _currentDevicePixelRatio {
-        void OnDestroy() {
-            D.assert(_wrapper != null);
-            _wrapper?.Destroy();
-            _wrapper = null;
-
-            Input_OnDisable();
+        void Update() {
+            _wrapper.onEditorUpdate();
+            _configurations = new Configurations();
-            _wrapper.Initiate(this, _currentWidth, _currentHeight, _currentDevicePixelRatio, new Dictionary<string, object>());
-            
+            onEnable();
+            _wrapper.Initiate(this, width: _currentWidth, height: _currentHeight, dpr: _currentDevicePixelRatio,
+                _configurations: _configurations);
+            _configurations.Clear();
-        void Update() {
-            _wrapper.onEditorUpdate();
+        void OnDestroy() {
+            D.assert(_wrapper != null);
+            _wrapper?.Destroy();
+            _wrapper = null;
+            Input_OnDisable();
-        void OnGUI()
-        {
+        void OnGUI() {
-                if (_wrapper.didDisplayMetricsChanged(_currentWidth, _currentHeight, _currentDevicePixelRatio)) {
-                    _wrapper.OnDisplayMetricsChanged(_currentWidth, _currentHeight, _currentDevicePixelRatio);
+                if (_wrapper.didDisplayMetricsChanged(width: _currentWidth, height: _currentHeight,
+                    dpr: _currentDevicePixelRatio)) {
+                    _wrapper.OnDisplayMetricsChanged(width: _currentWidth, height: _currentHeight,
+                        dpr: _currentDevicePixelRatio);
-                
-                GUI.DrawTexture(new Rect(0.0f, 0.0f, position.width, position.height), _wrapper.renderTexture);
-                Input_OnGUIEvent(Event.current);
+
+                GUI.DrawTexture(new Rect(0.0f, 0.0f, width: position.width, height: position.height),
+                    image: _wrapper.renderTexture);
+                Input_OnGUIEvent(evt: Event.current);
+        public UIWidgetsWindowType getWindowType() {
+            return UIWidgetsWindowType.EditorWindowPanel;
+        }
+
+        public bool isActive() {
+            return true;
+        }
+
+        public void startCoroutine(IEnumerator routing) {
+            this.StartCoroutine(coroutine: routing);
+        }
+
+        public void onNewFrameScheduled() {
+            Repaint();
+        }
+
+        public Offset windowPosToScreenPos(Offset offset) {
+            return offset;
+        }
+
+        public void mainEntry() {
+            main();
+        }
+
+        protected virtual void onEnable() {
+        }
+        protected void AddFont(string family, List<string> assets, List<int> weights) {
+            if (assets.Count != weights.Count) {
+                Debug.LogError($"The size of {family}‘s assets should be equal to the weights'.");
+                return;
+            }
+
+            var textFont = new TextFont {family = family};
+            var fonts = new Font[assets.Count];
+            for (var j = 0; j < assets.Count; j++) {
+                var font = new Font {asset = assets[index: j], weight = weights[index: j]};
+                fonts[j] = font;
+            }
+
+            textFont.fonts = fonts;
+            _configurations.AddFont(family,textFont);
+        }
+
-            return new Vector2(position.x, position.y);
+            return new Vector2(x: position.x, y: position.y);
         }
 
         int _buttonToPointerId(int buttonId) {
-            else if (buttonId == 1) {
+
+            if (buttonId == 1) {
                 return -2;
             }
 
         void Input_OnGUIEvent(Event evt) {
             if (evt.type == EventType.MouseDown) {
-                var pos = _getPointerPosition(evt.mousePosition);
-                _wrapper.OnPointerDown(pos, _buttonToPointerId(evt.button));
+                var pos = _getPointerPosition(position: evt.mousePosition);
+                _wrapper.OnPointerDown(pos: pos, _buttonToPointerId(buttonId: evt.button));
-                var pos = _getPointerPosition(evt.mousePosition);
-                _wrapper.OnPointerUp(pos, _buttonToPointerId(evt.button));
+                var pos = _getPointerPosition(position: evt.mousePosition);
+                _wrapper.OnPointerUp(pos: pos, _buttonToPointerId(buttonId: evt.button));
-                var pos = _getPointerPosition(evt.mousePosition);
-                _wrapper.OnMouseMove(pos);
+                var pos = _getPointerPosition(position: evt.mousePosition);
+                _wrapper.OnMouseMove(pos: pos);
-                var pos = _getPointerPosition(evt.mousePosition);
-                _wrapper.OnMouseMove(pos);
+                var pos = _getPointerPosition(position: evt.mousePosition);
+                _wrapper.OnMouseMove(pos: pos);
-                var pos = _getPointerPosition(evt.mousePosition);
-                _wrapper.OnMouseScroll(delta, pos);
+                var pos = _getPointerPosition(position: evt.mousePosition);
+                _wrapper.OnMouseScroll(delta: delta, pos: pos);
-            
-        }
-        
-        public void mainEntry() { 
-            main();
         }
 
         protected virtual void main() {
-            
-            
         }
     }
 }

com.unity.uiwidgets/Editor/UIWidgetsPanelEditor.cs

 using Unity.UIWidgets.engine;
 using Unity.UIWidgets.engine2;
+using Unity.UIWidgets.foundation;
 using UnityEditor;
 using UnityEditor.UI;
 using UnityEngine;
             base.OnInspectorGUI(); 
             var pixelRatioProperty = serializedObject.FindProperty("devicePixelRatioOverride");
             var antiAliasingProperty = serializedObject.FindProperty("hardwareAntiAliasing");
-            var ShowDebugLog = serializedObject.FindProperty("m_ShowDebugLog");
-            
-
-            EditorGUILayout.PropertyField(ShowDebugLog);
-            if (EditorGUI.EndChangeCheck()) {
-                UIWidgetsPanel.ShowDebugLog = ShowDebugLog.boolValue;
-            }
-            UIWidgetsPanel panel = (UIWidgetsPanel)target;
+            UIWidgetsPanel panel = (UIWidgetsPanel)target; 
+            serializedObject.ApplyModifiedProperties(); 
+        }
+        
-            serializedObject.ApplyModifiedProperties(); 
+        [MenuItem("UIWidgets/EnableDebug")]
+        public static void ToggleDebugMode(){
+            D.enableDebug = !D.enableDebug;
+        }
+        
+        [MenuItem("UIWidgets/EnableDebug",true)]
+        public static bool CurrentDebugModeState() {
+            Menu.SetChecked("UIWidgets/EnableDebug", D.enableDebug );
+            return true;
         }
     }
 }

com.unity.uiwidgets/Runtime/cupertino/date_picker.cs

 using System.Globalization;
 using System.Linq;
 using Unity.UIWidgets.animation;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.painting;
 using Unity.UIWidgets.rendering;
                 };
                 break;
             }
-             CupertinoThemeData themeData = CupertinoTheme.of(context);
+            CupertinoThemeData themeData = CupertinoTheme.of(context);
             return new MediaQuery(
               // The native iOS picker's text scaling is fixed, so we will also fix it
               // as well in our picker.
                     child: new DefaultTextStyle(
                       style: _textStyleFrom(context),
                       child: new Row(
-                          children:
-                              columns.Select((Widget child) => {
-                                      var result = new Expanded(child: child);
-                                      return (Widget) result;
-                              }).ToList()
+                          children: LinqUtils<Widget>.SelectList(columns, (Widget child) => {
+                              var result = new Expanded(child: child);
+                              return (Widget) result;
+                          })
                           )
                     )
                   )

com.unity.uiwidgets/Runtime/engine/DisplayMetrics.cs

                 }
 
 #if UNITY_ANDROID
-                this._devicePixelRatio = AndroidDevicePixelRatio();
+                _devicePixelRatio = AndroidDevicePixelRatio();
 #endif
 
 #if UNITY_WEBGL
                     float padding_left = metrics.Get<float>("padding_left");
                     float padding_right = metrics.Get<float>("padding_right");
 
-                    this._viewMetrics = new viewMetrics {
+                    _viewMetrics = new viewMetrics {
                         insets_bottom = insets_bottom,
                         insets_left = insets_left,
                         insets_right = insets_right,

com.unity.uiwidgets/Runtime/engine/UIWidgetsMessageManager.cs

 
         void UpdateNameIfNeed() {
 #if UNITY_IOS || UNITY_ANDROID || UNITY_WEBGL
-            var name = this.gameObject.name;
-            if (name != this._lastObjectName) {
+            var name = gameObject.name;
+            if (name != _lastObjectName) {
-                this._lastObjectName = name;
+                _lastObjectName = name;
             }
 #endif
         }

com.unity.uiwidgets/Runtime/engine2/UIWidgetsPanel.cs

 using System;
 using System.Collections;
 using System.Collections.Generic;
-using Unity.UIWidgets.editor2;
+using Unity.UIWidgets.engine2;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
 using UnityEngine;
 namespace Unity.UIWidgets.engine2 {
-
-    
+
+    [Serializable]
+    public struct Font {
+        public string asset;
+        public int weight;
+    }
+
+    [Serializable]
+    public struct TextFont {
+        public string family;
+        [SerializeField] public Font[] fonts;
+    }
+
     public interface IUIWidgetsWindow {
         Offset windowPosToScreenPos(Offset offset);
 
 
         UIWidgetsWindowType getWindowType();
     }
-
-    public partial class UIWidgetsPanel : RawImage, IUIWidgetsWindow {
-        UIWidgetsPanelWrapper _wrapper;
-
-        public float devicePixelRatioOverride;
-
-        public bool hardwareAntiAliasing;
-
-        public UIWidgetsWindowType getWindowType() {
-            return UIWidgetsWindowType.GameObjectPanel;
-        }
+    public class Configurations {
-        public bool isActive() {
-            return IsActive();
-        }
-
-        public void startCoroutine(IEnumerator routing) {
-            StartCoroutine(routing);
-        }
-
-        public void onNewFrameScheduled() {
-            
-        }
-
-        public Offset windowPosToScreenPos(Offset offset) {
-            Camera camera = null;
-            if (canvas.renderMode != RenderMode.ScreenSpaceCamera) {
-                camera = canvas.GetComponent<GraphicRaycaster>().eventCamera;
-            }
-
-            var pos = new Vector2(offset.dx, offset.dy);
-            pos = pos * _currentDevicePixelRatio / canvas.scaleFactor;
-            var rect = rectTransform.rect;
-            pos.x += rect.min.x;
-            pos.y = rect.max.y - pos.y;
-            var worldPos = rectTransform.TransformPoint(new Vector2(pos.x, pos.y));
-            var screenPos = RectTransformUtility.WorldToScreenPoint(camera, worldPos);
-            return new Offset(screenPos.x, Screen.height - screenPos.y);
-        }
+        private Dictionary<string, TextFont> _textFonts = new Dictionary<string, TextFont>();
-        [Serializable]
-        public struct Font {
-            public string asset;
-            public int weight;
+        public void Clear() {
+            _textFonts.Clear();
-
-        [Serializable]
-        public struct TextFont {
-            public string family;
-            [SerializeField] public Font[] fonts;
+        public void AddFont(string family, TextFont font) {
+           _textFonts[key: family] = font;
-
-        public TextFont[] fonts;
-
-        static object fontsToObject(TextFont[] textFont) {
-            if (textFont == null || textFont.Length == 0) {
+        public object fontsToObject() {
+            Dictionary<string, TextFont> settings = _textFonts;
+            if (settings == null || settings.Count == 0) {
-            var result = new object[textFont.Length];
-            for (int i = 0; i < textFont.Length; i++) {
+            var result = new object[settings.Count];
+            var i = 0;
+            foreach (var setting in settings) {
-                font.Add("family", textFont[i].family);
-                var dic = new Dictionary<string, object>[textFont[i].fonts.Length];
-                for (int j = 0; j < textFont[i].fonts.Length; j++) {
+                font.Add("family", value: setting.Key);
+                var dic = new Dictionary<string, object>[setting.Value.fonts.Length];
+                for (var j = 0; j < setting.Value.fonts.Length; j++) {
-                    if (textFont[i].fonts[j].asset.Length > 0) {
-                        dic[j].Add("asset", textFont[i].fonts[j].asset);
+                    if (setting.Value.fonts[j].asset.Length > 0) {
+                        dic[j].Add("asset", value: setting.Value.fonts[j].asset);
-                    if (textFont[i].fonts[j].weight > 0) {
-                        dic[j].Add("weight", textFont[i].fonts[j].weight);
+                    if (setting.Value.fonts[j].weight > 0) {
+                        dic[j].Add("weight", value: setting.Value.fonts[j].weight);
-                font.Add("fonts", dic);
+                font.Add("fonts", value: dic);
+                i++;
+    }
+
+    public partial class UIWidgetsPanel : RawImage, IUIWidgetsWindow {
+        public static List<UIWidgetsPanel> panels = new List<UIWidgetsPanel>();
+
+        static bool _ShowDebugLog;
+
+        public float devicePixelRatioOverride;
+
+        public bool hardwareAntiAliasing;
+
+        public TextFont[] fonts;
+
+        Configurations _configurations;
+
+        UIWidgetsPanelWrapper _wrapper;
 
         int _currentWidth {
             get { return Mathf.RoundToInt(rectTransform.rect.width * canvas.scaleFactor); }
 
         float _currentDevicePixelRatio {
             get {
-                float currentDpi = Screen.dpi;
+                var currentDpi = Screen.dpi;
                 if (currentDpi == 0) {
                     currentDpi = canvas.GetComponent<CanvasScaler>().fallbackScreenDPI;
                 }
         }
-
-        public bool m_ShowDebugLog = false;
-        public static List<UIWidgetsPanel> panels = new List<UIWidgetsPanel>();
-            get => _ShowDebugLog;
+            get { return _ShowDebugLog; }
-                foreach (var panel in panels) {
-                    panel.m_ShowDebugLog = value;
-                }
-
-        
-        static bool _ShowDebugLog = false;
+        protected virtual void Update() {
+            Input_Update();
+        }
-            var settings = new Dictionary<string, object>();
+            D.assert(_wrapper == null);
+            _configurations = new Configurations();
+            _wrapper = new UIWidgetsPanelWrapper();
+            onEnable();
-                settings.Add("fonts", fontsToObject(fonts));
+                foreach (var font in fonts) {
+                    AddFont(family: font.family, font: font);
+                }
-
-            D.assert(_wrapper == null);
-            _wrapper = new UIWidgetsPanelWrapper();
-            _wrapper.Initiate(this, _currentWidth, _currentHeight, _currentDevicePixelRatio, settings);
+            _wrapper.Initiate(this, width: _currentWidth, height: _currentHeight, dpr: _currentDevicePixelRatio,
+                _configurations: _configurations);
+            _configurations.Clear();
-
-            
-            _ShowDebugLog = m_ShowDebugLog;
-        public void mainEntry() {
-            main();
+        protected override void OnDisable() {
+            D.assert(_wrapper != null);
+            _wrapper?.Destroy();
+            _wrapper = null;
+            texture = null;
+            Input_OnDisable();
+            base.OnDisable();
+            panels.Remove(this);
-        protected virtual void main() {
+        protected virtual void OnGUI() {
+            Input_OnGUI();
-            if (_wrapper != null && _wrapper.didDisplayMetricsChanged(_currentWidth, _currentHeight, _currentDevicePixelRatio)) {
-                _wrapper.OnDisplayMetricsChanged(_currentWidth, _currentHeight, _currentDevicePixelRatio);
+            if (_wrapper != null && _wrapper.didDisplayMetricsChanged(width: _currentWidth, height: _currentHeight,
+                dpr: _currentDevicePixelRatio)) {
+                _wrapper.OnDisplayMetricsChanged(width: _currentWidth, height: _currentHeight,
+                    dpr: _currentDevicePixelRatio);
-        protected override void OnDisable() {
-            D.assert(_wrapper != null);
-            _wrapper?.Destroy();
-            _wrapper = null;
-            texture = null;
+        public UIWidgetsWindowType getWindowType() {
+            return UIWidgetsWindowType.GameObjectPanel;
+        }
+
+        public bool isActive() {
+            return IsActive();
+        }
+
+        public void startCoroutine(IEnumerator routing) {
+            StartCoroutine(routine: routing);
+        }
+
+        public void onNewFrameScheduled() {
+        }
+
+        public Offset windowPosToScreenPos(Offset offset) {
+            Camera camera = null;
+            if (canvas.renderMode != RenderMode.ScreenSpaceCamera) {
+                camera = canvas.GetComponent<GraphicRaycaster>().eventCamera;
+            }
+
+            var pos = new Vector2(x: offset.dx, y: offset.dy);
+            pos = pos * _currentDevicePixelRatio / canvas.scaleFactor;
+            var rect = rectTransform.rect;
+            pos.x += rect.min.x;
+            pos.y = rect.max.y - pos.y;
+            var worldPos = rectTransform.TransformPoint(new Vector2(x: pos.x, y: pos.y));
+            var screenPos = RectTransformUtility.WorldToScreenPoint(cam: camera, worldPoint: worldPos);
+            return new Offset(dx: screenPos.x, Screen.height - screenPos.y);
+        }
-            Input_OnDisable();
-            base.OnDisable();
-            
-            panels.Remove(this);
+        public void mainEntry() {
+            main();
-        protected virtual void Update() {
-            Input_Update();
+        protected virtual void onEnable() {
+        }
+        
+        protected void AddFont(string family, TextFont font) {
+            _configurations.AddFont(family,font);
-        protected virtual void OnGUI() {
-            Input_OnGUI();
+        protected void AddFont(string family, List<string> assets, List<int> weights) {
+            if (assets.Count != weights.Count) {
+                Debug.LogError($"The size of {family}‘s assets should be equal to the weights'.");
+                return;
+            }
+
+            var textFont = new TextFont {family = family};
+            var fonts = new Font[assets.Count];
+            for (var j = 0; j < assets.Count; j++) {
+                var font = new Font {asset = assets[index: j], weight = weights[index: j]};
+                fonts[j] = font;
+            }
+
+            textFont.fonts = fonts;
+            AddFont(family: family, font: textFont);
+        }
+        
+        protected virtual void main() {
+    enum UIWidgetsInputMode 
+    {
+        Mouse,
+        Touch
+    }
+
+        UIWidgetsInputMode _inputMode;
+
+        void _convertPointerData(PointerEventData evt, out Vector2? position, out int pointerId) {
+            position = _inputMode == UIWidgetsInputMode.Mouse
+                ? _getPointerPosition(Input.mousePosition)
+                : _getPointerPosition(evt);
+            pointerId = _inputMode == UIWidgetsInputMode.Mouse ? evt.pointerId : (-1 - evt.pointerId);
+        }
+
-            Camera worldCamera = canvas.worldCamera;
+            var worldCamera = canvas.worldCamera;
-                rectTransform, position, worldCamera, out var localPoint)) {
+                rect: rectTransform, screenPoint: position, cam: worldCamera, out var localPoint)) {
                 var scaleFactor = canvas.scaleFactor;
                 localPoint.x = (localPoint.x - rectTransform.rect.min.x) * scaleFactor;
                 localPoint.y = (rectTransform.rect.max.y - localPoint.y) * scaleFactor;
             return null;
         }
 
+        Vector2? _getPointerPosition(PointerEventData eventData) {
+            //refer to: https://zhuanlan.zhihu.com/p/37127981
+            Camera eventCamera = null;
+            if (canvas.renderMode != RenderMode.ScreenSpaceOverlay) {
+                eventCamera = canvas.GetComponent<GraphicRaycaster>().eventCamera;
+            }
+
+            Vector2 localPoint;
+            RectTransformUtility.ScreenPointToLocalPointInRectangle(rectTransform, eventData.position,
+                eventCamera, out localPoint);
+            var scaleFactor = canvas.scaleFactor;
+            localPoint.x = (localPoint.x - rectTransform.rect.min.x) * scaleFactor;
+            localPoint.y = (rectTransform.rect.max.y - localPoint.y) * scaleFactor;
+            return localPoint;
+        }
+
+            _inputMode = Input.mousePresent ? UIWidgetsInputMode.Mouse : UIWidgetsInputMode.Touch;
         }
 
         void Input_OnDisable() {
-            if (Input.touchCount == 0 && Input.mousePresent) {
+            //we only process hover events for desktop applications
+            if (_inputMode == UIWidgetsInputMode.Mouse) {
                 if (_isEntered) {
                     if (!Input.GetMouseButton(0) && !Input.GetMouseButton(1) && !Input.GetMouseButton(2)) {
                         if (_lastMousePosition.x != Input.mousePosition.x ||
         }
 
         void Input_OnGUI() {
-            Event e = Event.current;
+            var e = Event.current;
-                _wrapper.OnKeyDown(e);
+                _wrapper.OnKeyDown(e: e);
+            if (_inputMode != UIWidgetsInputMode.Mouse) {
+                return;
+            }
+            if (_inputMode != UIWidgetsInputMode.Mouse) {
+                return;
+            }
-        public void OnPointerDown(PointerEventData eventData) {
-            var pos = _getPointerPosition(Input.mousePosition);
-            _wrapper.OnPointerDown(pos, eventData.pointerId);
-        }
-
-        public void OnPointerUp(PointerEventData eventData) {
-            var pos = _getPointerPosition(Input.mousePosition);
-            _wrapper.OnPointerUp(pos, eventData.pointerId);
-        }
-
+            if (_inputMode != UIWidgetsInputMode.Mouse) {
+                return;
+            }
             D.assert(eventData.pointerId < 0);
             _isEntered = true;
             _lastMousePosition = Input.mousePosition;
+            if (_inputMode != UIWidgetsInputMode.Mouse) {
+                return;
+            }
+        public void OnPointerDown(PointerEventData eventData) {
+            _convertPointerData(eventData, out var pos, out var pointerId);
+            _wrapper.OnPointerDown(pos, pointerId);
+        }
+
+        public void OnPointerUp(PointerEventData eventData) {
+            _convertPointerData(eventData, out var pos, out var pointerId);
+            _wrapper.OnPointerUp(pos, pointerId);
+        }
+
-            var pos = _getPointerPosition(Input.mousePosition);
-            _wrapper.OnDrag(pos, eventData.pointerId);
+            _convertPointerData(eventData, out var pos, out var pointerId);
+            _wrapper.OnDrag(pos, pointerId);
         }
     }
 }

com.unity.uiwidgets/Runtime/engine2/UIWidgetsPanelWrapper.cs

 using Unity.UIWidgets.ui;
 using UnityEngine;
 
-namespace Unity.UIWidgets.editor2 {
-    
-#region Platform: Windows Specific Functionalities
+namespace Unity.UIWidgets.engine2 {
+    #region Platform: Windows Specific Functionalities
-        RenderTexture _renderTexture;
-    
-    
-        public RenderTexture renderTexture {
-            get { return _renderTexture; }
-        }
+        public RenderTexture renderTexture { get; private set; }
-            D.assert(_renderTexture == null);
+            D.assert(renderTexture == null);
-                width, height, RenderTextureFormat.ARGB32, 0) {
+                width: width, height: height, colorFormat: RenderTextureFormat.ARGB32, 0) {
-                autoGenerateMips = false,
+                autoGenerateMips = false
-            _renderTexture = new RenderTexture(desc) {hideFlags = HideFlags.HideAndDontSave};
-            _renderTexture.Create();
+            renderTexture = new RenderTexture(desc: desc) {hideFlags = HideFlags.HideAndDontSave};
+            renderTexture.Create();
-            _devicePixelRatio = devicePixelRatio;
+            this.devicePixelRatio = devicePixelRatio;
-            D.assert(_renderTexture != null);
-            ObjectUtils.SafeDestroy(_renderTexture);
-            _renderTexture = null;
+            D.assert(renderTexture != null);
+            ObjectUtils.SafeDestroy(obj: renderTexture);
+            renderTexture = null;
-            UIWidgetsPanel_onEnable(_ptr, _renderTexture.GetNativeTexturePtr(),
-                _width, _height, _devicePixelRatio, Application.streamingAssetsPath, font_settings);
+            UIWidgetsPanel_onEnable(ptr: _ptr, renderTexture.GetNativeTexturePtr(),
+                width: _width, height: _height, dpi: devicePixelRatio,
+                streamingAssetsPath: Application.streamingAssetsPath, font_settings: font_settings);
-            UIWidgetsPanel_onRenderTexture(_ptr,
-                _renderTexture.GetNativeTexturePtr(),
-                _width, _height, _devicePixelRatio);
+            UIWidgetsPanel_onRenderTexture(ptr: _ptr,
+                renderTexture.GetNativeTexturePtr(),
+                width: _width, height: _height, dpi: devicePixelRatio);
-            _renderTexture = null;
+            renderTexture = null;
-        [DllImport(NativeBindings.dllName)]
+        [DllImport(dllName: NativeBindings.dllName)]
-        [DllImport(NativeBindings.dllName)]
+        [DllImport(dllName: NativeBindings.dllName)]
-#endregion
+    #endregion
-#region  Platform: MacOs Specific Functionalities
+    #region Platform: MacOs Specific Functionalities
-
 public partial class UIWidgetsPanelWrapper {
     Texture _renderTexture;
     
 
         _width = width;
         _height = height;
-        _devicePixelRatio = devicePixelRatio;
+        this.devicePixelRatio = devicePixelRatio;
     }
 
     void _destroyRenderTexture() {
 
     void _enableUIWidgetsPanel(string font_settings) {
         D.assert(_renderTexture == null);
-        IntPtr native_tex_ptr = UIWidgetsPanel_onEnable(_ptr, _width, _height, _devicePixelRatio,
+        IntPtr native_tex_ptr = UIWidgetsPanel_onEnable(_ptr, _width, _height, devicePixelRatio,
             Application.streamingAssetsPath, font_settings);
         D.assert(native_tex_ptr != IntPtr.Zero);
 
     void _resizeUIWidgetsPanel() {
         D.assert(_renderTexture == null);
 
-        IntPtr native_tex_ptr = UIWidgetsPanel_onRenderTexture(_ptr, _width, _height, _devicePixelRatio);
+        IntPtr native_tex_ptr = UIWidgetsPanel_onRenderTexture(_ptr, _width, _height, devicePixelRatio);
         D.assert(native_tex_ptr != IntPtr.Zero);
 
         _renderTexture =
 
 #endif
 
-#endregion
-
-
-#region Window Common Properties and Functions
-
-public partial class UIWidgetsPanelWrapper {
-    public static UIWidgetsPanelWrapper current {
-        get { return Window.instance._panel; }
-    }
+    #endregion
-    IntPtr _ptr;
-    GCHandle _handle;
-    int _width;
-    int _height;
-    float _devicePixelRatio;
+    #region Window Common Properties and Functions
-    IUIWidgetsWindow _host;
+    public partial class UIWidgetsPanelWrapper {
+        public static UIWidgetsPanelWrapper current {
+            get { return Window.instance._panel; }
+        }
-    public IUIWidgetsWindow window {
-        get { return _host; }
-    }
+        IntPtr _ptr;
+        GCHandle _handle;
-    public Isolate isolate { get; private set; }
+        int _width;
+        int _height;
-    public float devicePixelRatio {
-        get { return _devicePixelRatio; }
-    }
+        public IUIWidgetsWindow window { get; private set; }
-    public void Initiate(IUIWidgetsWindow host, int width, int height, float dpr,
-        Dictionary<string, object> settings) {
-        D.assert(_renderTexture == null);
-        _recreateRenderTexture(width, height, dpr);
+        public Isolate isolate { get; private set; }
-        _handle = GCHandle.Alloc(this);
-        _ptr = UIWidgetsPanel_constructor((IntPtr) _handle, (int) host.getWindowType(), UIWidgetsPanel_entrypoint);
-        _host = host;
+        public float devicePixelRatio { get; private set; }
-        _enableUIWidgetsPanel(JSONMessageCodec.instance.toJson(settings));
-        NativeConsole.OnEnable();
-    }
+        public void Initiate(IUIWidgetsWindow host, int width, int height, float dpr, Configurations _configurations) {
+            D.assert(renderTexture == null);
+            _recreateRenderTexture(width: width, height: height, devicePixelRatio: dpr);
-    public void _entryPoint() {
-        try {
-            isolate = Isolate.current;
-            Window.instance._panel = this;
+            _handle = GCHandle.Alloc(this);
+            _ptr = UIWidgetsPanel_constructor((IntPtr) _handle, (int) host.getWindowType(),
+                entrypointCallback: UIWidgetsPanel_entrypoint);
+            window = host;
-            _host.mainEntry();
+            var fontsetting = new Dictionary<string, object>();
+            fontsetting.Add("fonts", _configurations.fontsToObject());
+            _enableUIWidgetsPanel(JSONMessageCodec.instance.toJson(message: fontsetting));
+            NativeConsole.OnEnable();
-        catch (Exception ex) {
-            Debug.LogException(new Exception("exception in main", ex));
+
+        public void _entryPoint() {
+            try {
+                isolate = Isolate.current;
+                Window.instance._panel = this;
+                window.mainEntry();
+            }
+            catch (Exception ex) {
+                Debug.LogException(new Exception("exception in main", innerException: ex));
+            }
-    }
-    public bool didDisplayMetricsChanged(int width, int height, float dpr) {
-        return width != _width || height != _height || dpr != _devicePixelRatio;
-    }
+        public bool didDisplayMetricsChanged(int width, int height, float dpr) {
+            return width != _width || height != _height || dpr != devicePixelRatio;
+        }
-    public void OnDisplayMetricsChanged(int width, int height, float dpr) {
-        if (_ptr != IntPtr.Zero && _renderTexture) {
-            if (_recreateRenderTexture(width, height, dpr)) {
-                _resizeUIWidgetsPanel();
+        public void OnDisplayMetricsChanged(int width, int height, float dpr) {
+            if (_ptr != IntPtr.Zero && renderTexture) {
+                if (_recreateRenderTexture(width: width, height: height, devicePixelRatio: dpr)) {
+                    _resizeUIWidgetsPanel();
+                }
-    }
+        public void Destroy() {
+            UIWidgetsPanel_onDisable(ptr: _ptr);
+            UIWidgetsPanel_dispose(ptr: _ptr);
+            _ptr = IntPtr.Zero;
+            _handle.Free();
+            _handle = default;
-    public void Destroy() {
-        UIWidgetsPanel_onDisable(_ptr);
-        UIWidgetsPanel_dispose(_ptr);
-        _ptr = IntPtr.Zero;
+            _disableUIWidgetsPanel();
+            D.assert(result: !isolate.isValid);
+        }
-        _handle.Free();
-        _handle = default;
+        bool _recreateRenderTexture(int width, int height, float devicePixelRatio) {
+            if (renderTexture != null && _width == width && _height == height &&
+                this.devicePixelRatio == devicePixelRatio) {
+                return false;
+            }
-        _disableUIWidgetsPanel();
-        D.assert(!isolate.isValid);
-    }
+            if (renderTexture) {
+                _destroyRenderTexture();
+            }
-    bool _recreateRenderTexture(int width, int height, float devicePixelRatio) {
-        if (_renderTexture != null && _width == width && _height == height &&
-            _devicePixelRatio == devicePixelRatio) {
-            return false;
+            _createRenderTexture(width: width, height: height, devicePixelRatio: devicePixelRatio);
+            return true;
-        if (_renderTexture) {
-            _destroyRenderTexture();
+        public int registerTexture(Texture texture) {
+            return UIWidgetsPanel_registerTexture(ptr: _ptr, texture.GetNativeTexturePtr());
-        _createRenderTexture(width, height, devicePixelRatio);
-        return true;
-    }
-
-    public int registerTexture(Texture texture) {
-        return UIWidgetsPanel_registerTexture(_ptr, texture.GetNativeTexturePtr());
-    }
-
-    public void unregisterTexture(int textureId) {
-        UIWidgetsPanel_unregisterTexture(_ptr, textureId);
-    }
+        public void unregisterTexture(int textureId) {
+            UIWidgetsPanel_unregisterTexture(ptr: _ptr, textureId: textureId);
+        }
-    public void markNewFrameAvailable(int textureId) {
-        UIWidgetsPanel_markNewFrameAvailable(_ptr, textureId);
-    }
+        public void markNewFrameAvailable(int textureId) {
+            UIWidgetsPanel_markNewFrameAvailable(ptr: _ptr, textureId: textureId);
+        }
-    public void onEditorUpdate() {
-        UIWidgetsPanel_onEditorUpdate(_ptr);
-    }
+        public void onEditorUpdate() {
+            UIWidgetsPanel_onEditorUpdate(ptr: _ptr);
+        }
-    delegate void UIWidgetsPanel_EntrypointCallback(IntPtr handle);
+        delegate void UIWidgetsPanel_EntrypointCallback(IntPtr handle);
-    [MonoPInvokeCallback(typeof(UIWidgetsPanel_EntrypointCallback))]
-    static void UIWidgetsPanel_entrypoint(IntPtr handle) {
-        GCHandle gcHandle = (GCHandle) handle;
-        UIWidgetsPanelWrapper panel = (UIWidgetsPanelWrapper) gcHandle.Target;
-        panel._entryPoint();
-    }
+        [MonoPInvokeCallback(typeof(UIWidgetsPanel_EntrypointCallback))]
+        static void UIWidgetsPanel_entrypoint(IntPtr handle) {
+            var gcHandle = (GCHandle) handle;
+            var panel = (UIWidgetsPanelWrapper) gcHandle.Target;
+            panel._entryPoint();
+        }
-    [DllImport(NativeBindings.dllName)]
-    static extern IntPtr UIWidgetsPanel_constructor(IntPtr handle, int windowType,
-        UIWidgetsPanel_EntrypointCallback entrypointCallback);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern IntPtr UIWidgetsPanel_constructor(IntPtr handle, int windowType,
+            UIWidgetsPanel_EntrypointCallback entrypointCallback);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_dispose(IntPtr ptr);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_dispose(IntPtr ptr);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onDisable(IntPtr ptr);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onDisable(IntPtr ptr);
-    [DllImport(NativeBindings.dllName)]
-    static extern int UIWidgetsPanel_registerTexture(IntPtr ptr, IntPtr nativeTexturePtr);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern int UIWidgetsPanel_registerTexture(IntPtr ptr, IntPtr nativeTexturePtr);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_unregisterTexture(IntPtr ptr, int textureId);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_unregisterTexture(IntPtr ptr, int textureId);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_markNewFrameAvailable(IntPtr ptr, int textureId);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_markNewFrameAvailable(IntPtr ptr, int textureId);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onEditorUpdate(IntPtr ptr);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onEditorUpdate(IntPtr ptr);
-}
+    }
-#endregion
+    #endregion
-#region Input Events Handles
+    #region Input Events Handles
-public partial class UIWidgetsPanelWrapper {
-    public void OnMouseMove(Vector2? pos) {
-        if (pos == null) {
-            return;
+    public partial class UIWidgetsPanelWrapper {
+        public void OnMouseMove(Vector2? pos) {
+            if (pos == null) {
+                return;
+            }
+
+            UIWidgetsPanel_onMouseMove(ptr: _ptr, x: pos.Value.x, y: pos.Value.y);
-        UIWidgetsPanel_onMouseMove(_ptr, pos.Value.x, pos.Value.y);
-    }
+        public void OnMouseScroll(Vector2 delta, Vector2? pos) {
+            if (pos == null) {
+                return;
+            }
-    public void OnMouseScroll(Vector2 delta, Vector2? pos) {
-        if (pos == null) {
-            return;
+            UIWidgetsPanel_onScroll(ptr: _ptr, x: delta.x, y: delta.y, px: pos.Value.x, py: pos.Value.y);
-        UIWidgetsPanel_onScroll(_ptr, delta.x, delta.y, pos.Value.x, pos.Value.y);
-    }
-    public void OnPointerDown(Vector2? pos, int pointerId) {
-        if (pos == null) {
-            return;
-        }
+        public void OnPointerDown(Vector2? pos, int pointerId) {
+            if (pos == null) {
+                return;
+            }
-        // mouse event
-        if (pointerId < 0) {
-            UIWidgetsPanel_onMouseDown(_ptr, pos.Value.x, pos.Value.y, pointerId);
+            // mouse event
+            if (pointerId < 0) {
+                UIWidgetsPanel_onMouseDown(ptr: _ptr, x: pos.Value.x, y: pos.Value.y, button: pointerId);
+            }
-    }
-    public void OnPointerUp(Vector2? pos, int pointerId) {
-        if (pos == null) {
-            return;
-        }
+        public void OnPointerUp(Vector2? pos, int pointerId) {
+            if (pos == null) {
+                return;
+            }
-        // mouse event
-        if (pointerId < 0) {
-            UIWidgetsPanel_onMouseUp(_ptr, pos.Value.x, pos.Value.y, pointerId);
+            // mouse event
+            if (pointerId < 0) {
+                UIWidgetsPanel_onMouseUp(ptr: _ptr, x: pos.Value.x, y: pos.Value.y, button: pointerId);
+            }
-    }
-    public void OnDrag(Vector2? pos, int pointerId) {
-        if (pos == null) {
-            return;
-        }
+        public void OnDrag(Vector2? pos, int pointerId) {
+            if (pos == null) {
+                return;
+            }
-        // mouse event
-        if (pointerId < 0) {
-            UIWidgetsPanel_onMouseMove(_ptr, pos.Value.x, pos.Value.y);
+            // mouse event
+            if (pointerId < 0) {
+                UIWidgetsPanel_onMouseMove(ptr: _ptr, x: pos.Value.x, y: pos.Value.y);
+            }
-    }
-    public void OnPointerLeave() {
-        UIWidgetsPanel_onMouseLeave(_ptr);
-    }
+        public void OnPointerLeave() {
+            UIWidgetsPanel_onMouseLeave(ptr: _ptr);
+        }
-    public void OnKeyDown(Event e) {
-        UIWidgetsPanel_onKey(_ptr, e.keyCode, e.type == EventType.KeyDown);
-        if (e.character != 0 || e.keyCode == KeyCode.Backspace) {
-            PointerEventConverter.KeyEvent.Enqueue(new Event(e));
-            // TODO: add on char
-            // UIWidgetsPanel_onChar(_ptr, e.character);
+        public void OnKeyDown(Event e) {
+            UIWidgetsPanel_onKey(ptr: _ptr, keyCode: e.keyCode, e.type == EventType.KeyDown);
+            if (e.character != 0 || e.keyCode == KeyCode.Backspace) {
+                PointerEventConverter.KeyEvent.Enqueue(new Event(other: e));
+                // TODO: add on char
+                // UIWidgetsPanel_onChar(_ptr, e.character);
+            }
-    }
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onChar(IntPtr ptr, char c);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onChar(IntPtr ptr, char c);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onKey(IntPtr ptr, KeyCode keyCode, bool isKeyDown);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onKey(IntPtr ptr, KeyCode keyCode, bool isKeyDown);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onMouseDown(IntPtr ptr, float x, float y, int button);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onMouseDown(IntPtr ptr, float x, float y, int button);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onMouseUp(IntPtr ptr, float x, float y, int button);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onMouseUp(IntPtr ptr, float x, float y, int button);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onMouseMove(IntPtr ptr, float x, float y);
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onMouseMove(IntPtr ptr, float x, float y);
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onMouseLeave(IntPtr ptr);
-    
-    [DllImport(NativeBindings.dllName)]
-    static extern void UIWidgetsPanel_onScroll(IntPtr ptr, float x, float y, float px, float py);
-}
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onMouseLeave(IntPtr ptr);
-#endregion
+        [DllImport(dllName: NativeBindings.dllName)]
+        static extern void UIWidgetsPanel_onScroll(IntPtr ptr, float x, float y, float px, float py);
+    }
+    #endregion
 }

com.unity.uiwidgets/Runtime/external/SplayTree.cs

 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
-namespace Unity.UIWidgets.external
-{    class SplayTree<TKey, TValue> : IDictionary<TKey, TValue> where TKey : IComparable<TKey> {
+namespace Unity.UIWidgets.external {    
+    class SplayTree<TKey, TValue> : IDictionary<TKey, TValue> where TKey : IComparable<TKey> {
         SplayTreeNode root;
         int count;
         int version = 0;

com.unity.uiwidgets/Runtime/external/simplejson/SimpleJSON.cs

         {
             try
             {
-                var item = m_Dict.Where(k => k.Value == aNode).First();
+                var item = LinqUtils<string, JSONNode>.WhereDictionary(m_Dict,(k => k.Value == aNode)).First();
                 m_Dict.Remove(item.Key);
                 return aNode;
             }

com.unity.uiwidgets/Runtime/foundation/assertions.cs

 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using Unity.UIWidgets.external;
 using UnityEngine;
 
 namespace Unity.UIWidgets.foundation {
             
             D.assert(() => {
                 IEnumerable<DiagnosticsNode> summaries =
-                    diagnostics.Where((DiagnosticsNode node) => node.level == DiagnosticLevel.summary);
+                    LinqUtils<DiagnosticsNode>.WhereList(diagnostics,((DiagnosticsNode node) => node.level == DiagnosticLevel.summary));
                 if (summaries.Count() > 1) {
                     return false;
                 }
-                    diagnostics.Where((DiagnosticsNode node) => node.level == DiagnosticLevel.summary);
+                    LinqUtils<DiagnosticsNode>.WhereList(diagnostics,((DiagnosticsNode node) => node.level == DiagnosticLevel.summary));
                 List<DiagnosticsNode> message = new List<DiagnosticsNode>() {
                     new ErrorSummary("UIWidgetsError contained multiple error summaries."),
                     new ErrorDescription(
 
         public override string ToString() {
             TextTreeRenderer renderer = new TextTreeRenderer(wrapWidth: 400000000);
-            return string.Join("\n", diagnostics.Select((DiagnosticsNode node) => renderer.render(node).TrimEnd()));
+            return string.Join("\n", LinqUtils<string,DiagnosticsNode>.SelectList(diagnostics,((DiagnosticsNode node) => renderer.render(node).TrimEnd())));
         }
 
         public static void reportError(UIWidgetsErrorDetails details) {

com.unity.uiwidgets/Runtime/foundation/collections.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.InternalBridge;
 
 namespace Unity.UIWidgets.foundation {
             if (it == null) {
                 return null;
             }
-
-            return "{ " + string.Join(", ", it.Select(item => item.ToString())) + " }";
+            return "{ " + string.Join(", ", LinqUtils<string,T>.SelectList(it,(item => item.ToString()))) + " }";
         }
 
         public static void reset<T>(this List<T> list, int size) {

com.unity.uiwidgets/Runtime/foundation/debug.cs

 using System;
 using System.Diagnostics;
 using System.Linq;
-using Unity.UIWidgets.engine2;
+using UnityEngine;
 using Canvas = Unity.UIWidgets.ui.Canvas;
 using Color = Unity.UIWidgets.ui.Color;
 using Debug = UnityEngine.Debug;
+    
+    
-        public static void logError(string message, Exception ex = null) {
-            Debug.LogException(new AssertionError(message, ex));
-        }
-
-        [Conditional("UNITY_ASSERTIONS")]
-        public static void assert(Func<bool> result, Func<string> message = null) {
-            if (UIWidgetsPanel.ShowDebugLog && !result()) {
-                throw new AssertionError(message != null ? message() : "");
-            }
-        }
-
-        [Conditional("UNITY_ASSERTIONS")]
-        public static void assert(bool result, Func<string> message = null) {
-            if (UIWidgetsPanel.ShowDebugLog && !result) {
-                throw new AssertionError(message != null ? message() : "");
-            }
-        }
-
-        public static bool debugPaintPointersEnabled = false;
+        public static bool debugPaintPointersEnabled;
-        public static bool debugPaintBaselinesEnabled = false;
+        public static bool debugPaintBaselinesEnabled;
-        public static bool debugPaintSizeEnabled = false;
+        public static bool debugPaintSizeEnabled;
-        public static bool debugRepaintRainbowEnabled = false;
+        public static bool debugRepaintRainbowEnabled;
-        public static bool debugPaintLayerBordersEnabled = false;
+        public static bool debugPaintLayerBordersEnabled;
 
         public static bool debugPrintMarkNeedsLayoutStacks = false;
 
         public static HSVColor debugCurrentRepaintColor =
             HSVColor.fromAHSV(0.4f, 60.0f, 1.0f, 1.0f);
 
-        public static void _debugDrawDoubleRect(Canvas canvas, Rect outerRect, Rect innerRect, Color color) {
-            Path path = new Path();
+        public static int? debugFloatPrecision;
+
+        public static void logError(string message, Exception ex = null) {
+            Debug.LogException(new AssertionError(message: message, innerException: ex));
+        }
+
+        [Conditional("UNITY_ASSERTIONS")]
+        public static void assert(Func<bool> result, Func<string> message = null) {
+            if ( enableDebug && !result() ) {
+                throw new AssertionError(message != null ? message() : "");
+            }
+        }
+
+        [Conditional("UNITY_ASSERTIONS")]
+        public static void assert(bool result, Func<string> message = null) {
+            if ( enableDebug && !result  ) {
+                throw new AssertionError(message != null ? message() : "");
+            }
+        }
+
+        static bool? _enableDebug = null;
+        public static bool enableDebug {
+            get {
+                if (_enableDebug == null) {
+                    _enableDebug = PlayerPrefs.GetInt("UIWidgetsDebug") == 1;
+                }
+                return _enableDebug.Value;
+            }
+            set {
+                if (_enableDebug == value) {
+                    return;
+                }
+                _enableDebug = value;
+                PlayerPrefs.SetInt("UIWidgetsDebug",value ? 1 : 0);
+            }
+        }
+        
+        public static void _debugDrawDoubleRect(Canvas canvas, Rect outerRect, Rect innerRect, Color color) { 
+            var path = new Path();
-            path.addRect(outerRect);
-            path.addRect(innerRect);
+            path.addRect(rect: outerRect);
+            path.addRect(rect: innerRect);
-            canvas.drawPath(path, paint);
+            canvas.drawPath(path: path, paint: paint);
-                    _debugDrawDoubleRect(canvas, outerRect, innerRect, new Color(0x900090FF));
-                    _debugDrawDoubleRect(canvas, innerRect.inflate(outlineWidth).intersect(outerRect), innerRect,
+                    _debugDrawDoubleRect(canvas: canvas, outerRect: outerRect, innerRect: innerRect,
+                        new Color(0x900090FF));
+                    _debugDrawDoubleRect(canvas: canvas,
+                        innerRect.inflate(delta: outlineWidth).intersect(other: outerRect), innerRect: innerRect,
-                    Paint paint = new Paint();
+                    var paint = new Paint();
-                    canvas.drawRect(outerRect, paint);
+                    canvas.drawRect(rect: outerRect, paint: paint);
                 }
 
                 return true;
             bool? debugPaintPointersEnabled = null,
             bool? debugPaintLayerBordersEnabled = null,
             bool? debugRepaintRainbowEnabled = null) {
-            bool needRepaint = false;
+            var needRepaint = false;
             if (debugPaintSizeEnabled != null && debugPaintSizeEnabled != D.debugPaintSizeEnabled) {
                 D.debugPaintSizeEnabled = debugPaintSizeEnabled.Value;
                 needRepaint = true;
                 }*/
             }
         }
-        
-        public static int? debugFloatPrecision;
 
         public static string debugFormatFloat(float? value) {
             if (value == null) {
                 return value.Value.ToString($"N{debugFloatPrecision}");
             }
 
-            return value.Value.ToString($"N1");
+            return value.Value.ToString("N1");
         }
     }
 
 
-        public AssertionError(string message) : base(message) {
+        public AssertionError(string message) : base(message: message) {
-        public AssertionError(string message, Exception innerException = null) : base(message) {
+        public AssertionError(string message, Exception innerException = null) : base(message: message) {
             this.innerException = innerException;
         }
 
                 var lines = stackTrace.Split('\n');
                 var strippedLines = lines.Skip(1);
 
-                return string.Join("\n", strippedLines);
+                return string.Join("\n", values: strippedLines);
             }
         }
     }

com.unity.uiwidgets/Runtime/foundation/diagnostics.cs

 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.ui;
 using UnityEngine;
 
                 builder.writeStretched(config.suffixLineOne, builder.wrapWidth.Value);
             }
 
-            IEnumerable<DiagnosticsNode> propertiesIterable = node.getProperties().Where(
+            IEnumerable<DiagnosticsNode> propertiesIterable = LinqUtils<DiagnosticsNode>.WhereList(node.getProperties(), (
-            );
+            ));
             List<DiagnosticsNode> properties;
             if (_maxDescendentsTruncatableNode >= 0 && node.allowTruncate) {
                 if (propertiesIterable.Count() < _maxDescendentsTruncatableNode) {
             }
 
             if (parentConfiguration != null && !parentConfiguration.lineBreakProperties) {
-                return string.Join(", ", value.Select(v => v.ToString()).ToArray());
+               return string.Join(", ", LinqUtils<string, T>.SelectList(value, (v => v.ToString())));
-
-            return string.Join(style == DiagnosticsTreeStyle.singleLine ? ", " : "\n",
-                value.Select(v => v.ToString()).ToArray());
+            return string.Join(style == DiagnosticsTreeStyle.singleLine ? ", " : "\n", 
+                LinqUtils<string, T>.SelectList(value,  (v => v.ToString())));
         }
 
         public override DiagnosticLevel level {
         public override Dictionary<string, object> toJsonMap(DiagnosticsSerializationDelegate Delegate) {
             var json = base.toJsonMap(Delegate);
             if (value != null) {
-                json["values"] = value.Select(v => v.ToString()).ToList();
+                json["values"] = LinqUtils<string, T>.SelectList(value, (v => v.ToString()));
             }
 
             return json;
                 result.Append(joiner);
                 DiagnosticPropertiesBuilder builder = new DiagnosticPropertiesBuilder();
                 debugFillProperties(builder);
-                result.Append(string.Join(joiner,
-                    builder.properties.Where(n => !n.isFiltered(minLevel)).Select(n => n.ToString()).ToArray())
+                result.Append(string.Join(joiner,LinqUtils<string,DiagnosticsNode>.SelectList(
+                    LinqUtils<DiagnosticsNode>.WhereList(builder.properties, (n => !n.isFiltered(minLevel)))
+                    ,(n => n.ToString())))
                 );
                 shallowString = result.ToString();
                 return true;

com.unity.uiwidgets/Runtime/gestures/hit_test.cs

 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.rendering;
 using Unity.UIWidgets.ui;
 
         public override string ToString() {
             return
-                $"HitTestResult({(_path.isEmpty() ? "<empty path>" : string.Join(", ", _path.Select(x => x.ToString()).ToArray()))})";
-        }
+                $"HitTestResult({(_path.isEmpty() ? "<empty path>" : string.Join(", ", LinqUtils<string,HitTestEntry>.SelectList(_path, (x => x.ToString())) ))})";
+           }
     }
 }

com.unity.uiwidgets/Runtime/material/bottom_navigation_bar.cs

 using System.Linq;
 using uiwidgets;
 using Unity.UIWidgets.animation;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.painting;
         public float horizontalLeadingOffset {
             get {
                 float weightSum(IEnumerable<Animation<float>> animations) {
-                    return animations.Select(state._evaluateFlex).Sum();
+                    return LinqUtils<float,Animation<float>>.SelectList(animations, state._evaluateFlex).Sum();
-                float allWeights = weightSum(state._animations);
+                float allWeights = weightSum(state._animations); 
                 float leadingWeights = weightSum(state._animations.GetRange(0, index ?? 0));
 
                 return (leadingWeights + state._evaluateFlex(state._animations[index ?? 0]) / 2.0f) /

com.unity.uiwidgets/Runtime/material/button_bar.cs

 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.painting;
 using Unity.UIWidgets.rendering;
                     mainAxisAlignment: alignment ?? barTheme?.alignment ?? MainAxisAlignment.end,
                     mainAxisSize: mainAxisSize ?? barTheme?.mainAxisSize ?? MainAxisSize.max,
                     overflowDirection: overflowDirection ?? barTheme?.overflowDirection ?? VerticalDirection.down,
-                    children: children.Select((Widget childWidget) => {
+                    children: LinqUtils<Widget>.SelectList(children,((Widget childWidget) => {
-                    }).ToList(),
+                    })),
                     overflowButtonSpacing: overflowButtonSpacing
                 )
             );

com.unity.uiwidgets/Runtime/material/data_table.cs

 using System.Linq;
 using uiwidgets;
 using Unity.UIWidgets.animation;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.painting;
             List<TableColumnWidth> tableColumns =
                 new List<TableColumnWidth>(new TableColumnWidth[columns.Count + (displayCheckboxColumn ? 1 : 0)]);
             
-            List<TableRow> tableRows = Enumerable.Range(0, rows.Count + 1).Select((index) => {
-                return new TableRow(
-                    key: index == 0 ? _headingRowKey : rows[index - 1].key,
-                    decoration: index > 0 && rows[index - 1].selected
-                        ? _kSelectedDecoration
-                        : _kUnselectedDecoration,
-                    children: new List<Widget>(new Widget[tableColumns.Count])
-                );
-            }).ToList();
+            List<TableRow> tableRows = LinqUtils<TableRow,int>.SelectList(Enumerable.Range(0, rows.Count + 1), (index) => {
+                    return new TableRow(
+                        key: index == 0 ? _headingRowKey : rows[index - 1].key,
+                        decoration: index > 0 && rows[index - 1].selected
+                            ? _kSelectedDecoration
+                            : _kUnselectedDecoration,
+                        children: new List<Widget>(new Widget[tableColumns.Count])
+                    );
+                });
 
             int rowIndex;
 
 
                 displayColumnIndex += 1;
             }
-
-                columnWidths: tableColumns.Select((x, i) => new {x, i})
-                    .ToDictionary(a => a.i, a => a.x),
+                columnWidths: LinqUtils<int, TableColumnWidth>.SelectDictionary(tableColumns, ((TableColumnWidth x) => tableColumns.IndexOf(x))),
                 children: tableRows
             );
         }

com.unity.uiwidgets/Runtime/material/dropdown.cs

 using uiwidgets;
 using Unity.UIWidgets.animation;
 using Unity.UIWidgets.async2;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.material;
         ) :
             base(key: key) {
             D.assert(items == null || items.isEmpty() || value == null ||
-                     items.Where((DropdownMenuItem<T> item) => { return item.value.Equals(value); }).Count() == 1,
+                     LinqUtils<DropdownMenuItem<T>>.WhereList(items,((DropdownMenuItem<T> item) => { return item.value.Equals(value); })).Count() == 1,
                 () => "There should be exactly one item with [DropdownButton]'s value: " +
                       $"{value}. \n" +
                       "Either zero or 2 or more [DropdownMenuItem]s were detected " +
             }
 
             D.assert(widget.value == null ||
-                     widget.items.Where((DropdownMenuItem<T> item) => item.value.Equals(widget.value))
-                         .ToList().Count == 1);
+                     LinqUtils<DropdownMenuItem<T>>.WhereList(widget.items,((DropdownMenuItem<T> item) => item.value.Equals(widget.value))
+                         ).Count == 1);
             _selectedIndex = null;
             for (int itemIndex = 0; itemIndex < widget.items.Count; itemIndex++) {
                 if (widget.items[itemIndex].value.Equals(widget.value)) {
                     alignment: AlignmentDirectional.centerStart,
                     children: widget.isDense
                         ? items
-                        : items.Select((Widget item) => {
+                        : LinqUtils<Widget>.SelectList(items,(Widget item) => {
-                        }).ToList()
-                );
+                        }));
             }
 
             Icon defaultIcon = new Icon(Icons.arrow_drop_down);

com.unity.uiwidgets/Runtime/material/navigation_rail.cs

 using System.Collections.Generic;
 using System.Linq;
 using Unity.UIWidgets.animation;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.painting;
 using Unity.UIWidgets.rendering;
         }
 
         void _initControllers() {
-            _destinationControllers = widget.destinations.Select((destination, i) => {
-                var result = new AnimationController(
-                    duration: ThemeUtils.kThemeAnimationDuration,
-                    vsync: this
-                );
-                result.addListener(_rebuild);
-                return result;
-            }).ToList();
-            _destinationAnimations = _destinationControllers.Select((AnimationController controller) => controller.view)
-                .ToList();
+            _destinationControllers = LinqUtils<AnimationController, NavigationRailDestination>.SelectList(widget.destinations, ((destination) => {
+                    var result = new AnimationController(
+                        duration: ThemeUtils.kThemeAnimationDuration,
+                        vsync: this
+                    );
+                    result.addListener(_rebuild);
+                    return result;
+                }));
+            _destinationAnimations = LinqUtils<Animation<float>, AnimationController>.SelectList(_destinationControllers,((AnimationController controller) => controller.view));
             _destinationControllers[widget.selectedIndex ?? 0].setValue(1.0f);
             _extendedController = new AnimationController(
                 duration: ThemeUtils.kThemeAnimationDuration,

com.unity.uiwidgets/Runtime/material/paginated_data_table.cs

 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.material;
         DataRow _getBlankRowFor(int index) {
             return DataRow.byIndex(
                 index: index,
-                cells: widget.columns.Select((DataColumn column) => DataCell.empty).ToList()
-            );
+                cells:  LinqUtils<DataCell,DataColumn>.SelectList(widget.columns,((DataColumn column) => DataCell.empty))
+                );
-            List<DataCell> cells = widget.columns.Select((DataColumn column) => {
-                if (!column.numeric) {
-                    haveProgressIndicator = true;
-                    return new DataCell(new CircularProgressIndicator());
-                }
-
-                return DataCell.empty;
-            }).ToList();
+            List<DataCell> cells = LinqUtils<DataCell, DataColumn>.SelectList(widget.columns,((DataColumn column) => {
+                    if (!column.numeric) {
+                        haveProgressIndicator = true;
+                        return new DataCell(new CircularProgressIndicator());
+                    }
+                    
+                    return DataCell.empty;
+                }));
             if (!haveProgressIndicator) {
                 haveProgressIndicator = true;
                 cells[0] = new DataCell(new CircularProgressIndicator());
 
             if (widget.actions != null) {
                 headerWidgets.AddRange(
-                    widget.actions.Select((Widget action) => {
-                        return new Padding(
-                            padding: EdgeInsetsDirectional.only(
-                                start: 24.0f - 8.0f * 2.0f),
-                            child: action
-                        );
-                    }).ToList()
+                    LinqUtils<Widget>.SelectList(widget.actions, ((Widget action) => {
+                    return new Padding(
+                        padding: EdgeInsetsDirectional.only(
+                            start: 24.0f - 8.0f * 2.0f),
+                        child: action
+                    );
+                }))
                 );
             }
 
-                List<Widget> availableRowsPerPage = widget.availableRowsPerPage
-                    .Where((int value) => value <= _rowCount || value == widget.rowsPerPage)
-                    .Select((int value) => {
+                List<Widget> availableRowsPerPage = LinqUtils<Widget,int>.SelectList(
+                    LinqUtils<int>.WhereList(widget.availableRowsPerPage, ((int value) => value <= _rowCount || value == widget.rowsPerPage)), 
+                    (int value) => {
-                    }).ToList();
+                    });
                 footerWidgets.AddRange(new List<Widget>() {
                     new Container(width: 14.0f), // to match trailing padding in case we overflow and end up scrolling
                     new Text(localizations.rowsPerPageTitle),

com.unity.uiwidgets/Runtime/material/range_slider.cs

 using System.Linq;
 using Unity.UIWidgets.animation;
 using Unity.UIWidgets.async2;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.painting;
         const float _minPreferredTrackWidth = 144.0f;
 
         float _maxSliderPartWidth {
-            get { return Mathf.Max(_sliderPartSizes.Select((Size size) => size.width).ToArray()); }
+            get {
+                return Mathf.Max(LinqUtils<float, Size>.SelectArray(_sliderPartSizes,((Size size) => size.width)));
+            }
-            get { return Mathf.Max(_sliderPartSizes.Select((Size size) => size.height).ToArray()); }
+            get {
+                return Mathf.Max(LinqUtils<float,Size>.SelectArray(_sliderPartSizes,((Size size) => size.height)));
+            }
         }
 
         List<Size> _sliderPartSizes {

com.unity.uiwidgets/Runtime/material/text_selection.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.rendering;
 using Unity.UIWidgets.service;
         }
 
         public override void debugVisitOnstageChildren(ElementVisitor visitor) {
-            foreach (var child in children.Where(_shouldPaint)) {
+            foreach (var child in LinqUtils<Element>.WhereList(children,(_shouldPaint))) {
                 visitor(child);
             }
         }

com.unity.uiwidgets/Runtime/painting/borders.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
 using UnityEngine;
 
         public override ShapeBorder scale(float t) {
             return new _CompoundBorder(
-                borders.Select(border => border.scale(t)).ToList()
+                LinqUtils<ShapeBorder>.SelectList(borders,(border => border.scale(t)))
             );
         }
 
 
         public override string ToString() {
             return string.Join(" + ",
-                ((IList<ShapeBorder>) borders).Reverse().Select((border) => border.ToString()));
+                (LinqUtils<string,ShapeBorder>.SelectList(((IList<ShapeBorder>)borders).Reverse(),((border) => border.ToString())))
+            );
         }
     }
 

com.unity.uiwidgets/Runtime/painting/gradient.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.animation;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.external;
 using Unity.UIWidgets.ui;
 
             D.assert(colors.Count >= 2, () => "colors list must have at least two colors");
             float separation = 1.0f / (colors.Count - 1);
-
-            return Enumerable.Range(0, colors.Count).Select(i => i * separation).ToList();
+            return LinqUtils<float, int>.SelectList(Enumerable.Range(0, colors.Count), (i => i * separation));
         }
 
         public abstract Shader createShader(Rect rect, TextDirection? textDirection = null);
             return new LinearGradient(
                 begin: begin,
                 end: end,
-                colors: colors.Select(color => Color.lerp(null, color, factor)).ToList(),
+                colors: LinqUtils<Color>.SelectList(colors,(color => Color.lerp(null, color, factor))),
                 stops: stops,
                 tileMode: tileMode
             );
             return new RadialGradient(
                 center: center,
                 radius: radius,
-                colors: colors.Select(color => Color.lerp(null, color, factor)).ToList(),
+                colors: LinqUtils<Color>.SelectList(colors,(color => Color.lerp(null, color, factor))),
                 stops: stops,
                 tileMode: tileMode
             );
                 center: center,
                 startAngle: startAngle,
                 endAngle: endAngle,
-                colors: colors.Select(color => Color.lerp(null, color, factor)).ToList(),
+                colors: LinqUtils<Color>.SelectList(colors,(color => Color.lerp(null, color, factor))),
                 stops: stops,
                 tileMode: tileMode
             );

com.unity.uiwidgets/Runtime/painting/image_provider.cs

 using System.IO;
 using System.Text;
 using Unity.UIWidgets.async2;
-using Unity.UIWidgets.editor2;
 using Unity.UIWidgets.engine2;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;

com.unity.uiwidgets/Runtime/painting/image_stream.cs

 using System.Collections.Generic;
 using System.Linq;
 using Unity.UIWidgets.async2;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.scheduler2;
 using Unity.UIWidgets.ui;
                 return;
             }
 
-            var localListeners = _listeners.Select(l => l).ToList();
+            var localListeners = LinqUtils<ImageStreamListener>.SelectList(_listeners,(l => l));
             foreach (var listener in localListeners) {
                 try {
                     listener.onImage(image, false);
                 informationCollector: informationCollector,
                 silent: silent
             );
-
-            var localErrorListeners = _listeners
-                .Select(l => l.onError)
-                .Where(l => l != null)
-                .ToList();
-
+            
+            var localErrorListeners = LinqUtils<ImageErrorListener>.WhereList(
+                LinqUtils<ImageErrorListener,ImageStreamListener>.SelectList(_listeners, (l => l.onError)),
+                (l => l != null));
+            
             if (localErrorListeners.isEmpty()) {
                 UIWidgetsError.reportError(_currentError);
             }

com.unity.uiwidgets/Runtime/painting/text_span.cs

 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.ui;
             if (children == null) {
                 return new List<DiagnosticsNode>();
             }
-
-            return children.Select((child) => {
-                if (child != null) {
-                    return child.toDiagnosticsNode();
-                }
-                else {
-                    return DiagnosticsNode.message("<null child>");
-                }
-            }).ToList();
+            return LinqUtils<DiagnosticsNode, InlineSpan>.SelectList(children,((child) => {
+                    if (child != null) {
+                        return child.toDiagnosticsNode();
+                    }
+                    else {
+                        return DiagnosticsNode.message("<null child>");
+                    }
+                }));
         }
 
 

com.unity.uiwidgets/Runtime/painting/text_style.cs

 using System.Linq;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
-using UnityEngine;
-using Color = Unity.UIWidgets.ui.Color;
-using FontStyle = Unity.UIWidgets.ui.FontStyle;
+        const string _kDefaultDebugLabel = "unknown";
+
+        const string _kColorForegroundWarning = "Cannot provide both a color and a foreground\n" +
+                                                "The color argument is just a shorthand for 'foreground: new Paint()..color = color'.";
+
+        const string _kColorBackgroundWarning = "Cannot provide both a backgroundColor and a background\n" +
+                                                "The backgroundColor argument is just a shorthand for 'background: new Paint()..color = color'.";
+
-        public readonly bool inherit;
+
+        public readonly Paint background;
+        public readonly Color backgroundColor;
-        public readonly Color backgroundColor;
-        public readonly float? fontSize;
-        public readonly FontWeight fontWeight;
-        public readonly FontStyle? fontStyle;
-        public readonly float? letterSpacing;
-        public readonly float? wordSpacing;
-        public readonly TextBaseline? textBaseline;
-        public readonly float? height;
+        public readonly string debugLabel;
-        public readonly Paint foreground;
-        public readonly Paint background;
-        public readonly List<BoxShadow> shadows;
-
-        public List<string> fontFamilyFallback {
-            get { return _fontFamilyFallback; }
-        }
-
-        readonly List<string> _fontFamilyFallback;
-        public readonly string debugLabel;
-
-        const string _kDefaultDebugLabel = "unknown";
-
-        const string _kColorForegroundWarning = "Cannot provide both a color and a foreground\n" +
-                                                "The color argument is just a shorthand for 'foreground: new Paint()..color = color'.";
-
-        const string _kColorBackgroundWarning = "Cannot provide both a backgroundColor and a background\n" +
-                                                "The backgroundColor argument is just a shorthand for 'background: new Paint()..color = color'.";
+        public readonly float? fontSize;
+        public readonly FontStyle? fontStyle;
+        public readonly FontWeight fontWeight;
+        public readonly Paint foreground;
+        public readonly float? height;
+        public readonly bool inherit;
+        public readonly float? letterSpacing;
+        public readonly List<BoxShadow> shadows;
+        public readonly TextBaseline? textBaseline;
+        public readonly float? wordSpacing;
 
         public TextStyle(bool inherit = true,
             Color color = null,
             this.decorationStyle = decorationStyle;
             this.decorationThickness = decorationThickness;
             this.fontFamily = fontFamily;
-            _fontFamilyFallback = fontFamilyFallback;
+            this.fontFamilyFallback = fontFamilyFallback;
             this.debugLabel = debugLabel;
             this.foreground = foreground;
             this.background = background;
 
+        public List<string> fontFamilyFallback { get; }
+
+        public bool Equals(TextStyle other) {
+            if (ReferenceEquals(null, objB: other)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, objB: other)) {
+                return true;
+            }
+
+            return inherit == other.inherit &&
+                   Equals(objA: color, objB: other.color) &&
+                   Equals(objA: backgroundColor, objB: other.backgroundColor) &&
+                   fontSize.Equals(other: other.fontSize) &&
+                   fontWeight == other.fontWeight &&
+                   fontStyle == other.fontStyle &&
+                   letterSpacing.Equals(other: other.letterSpacing) &&
+                   wordSpacing.Equals(other: other.wordSpacing) &&
+                   textBaseline == other.textBaseline &&
+                   height.Equals(other: other.height) &&
+                   Equals(objA: decoration, objB: other.decoration) &&
+                   Equals(objA: decorationColor, objB: other.decorationColor) &&
+                   decorationStyle == other.decorationStyle &&
+                   decorationThickness == other.decorationThickness &&
+                   Equals(objA: foreground, objB: other.foreground) &&
+                   Equals(objA: background, objB: other.background) &&
+                   fontFamilyFallback.equalsList(list: other.fontFamilyFallback) &&
+                   shadows.equalsList(list: other.shadows) &&
+                   fontFeatures.equalsList(list: other.fontFeatures) &&
+                   string.Equals(a: fontFamily, b: other.fontFamily);
+        }
+
-            if (ReferenceEquals(this, other))
+            if (ReferenceEquals(this, objB: other)) {
+            }
+
             if (inherit != other.inherit ||
                 fontFamily != other.fontFamily ||
                 fontSize != other.fontSize ||
                 height != other.height ||
                 foreground != other.foreground ||
                 background != other.background ||
-                !shadows.equalsList(other.shadows) ||
-                !fontFeatures.equalsList(other.fontFeatures) ||
-                !fontFamilyFallback.equalsList(other.fontFamilyFallback)) {
+                !shadows.equalsList(list: other.shadows) ||
+                !fontFeatures.equalsList(list: other.fontFeatures) ||
+                !fontFamilyFallback.equalsList(list: other.fontFamilyFallback)) {
                 return RenderComparison.layout;
             }
 
         ) {
             D.assert(textScaleFactor != null);
             D.assert(maxLines == null || maxLines > 0);
-            return new ui.ParagraphStyle(
+            return new ParagraphStyle(
-                textDirection: textDirection,
+                textDirection ?? TextDirection.ltr,
                 fontWeight: fontWeight ?? this.fontWeight,
                 fontStyle: fontStyle ?? this.fontStyle,
                 fontFamily: fontFamily ?? this.fontFamily,
                     : new ui.StrutStyle(
                         fontFamily: strutStyle.fontFamily,
                         fontFamilyFallback: strutStyle.fontFamilyFallback,
-                        fontSize: strutStyle.fontSize == null ? null : strutStyle.fontSize * textScaleFactor,
+                        strutStyle.fontSize == null ? null : strutStyle.fontSize * textScaleFactor,
                         height: strutStyle.height,
                         leading: strutStyle.leading,
                         fontWeight: strutStyle.fontWeight,
             float heightFactor = 1.0f,
             float heightDelta = 0.0f
         ) {
-            D.assert(fontSize != null || (fontSizeFactor == 1.0f && fontSizeDelta == 0.0f));
+            D.assert(fontSize != null || fontSizeFactor == 1.0f && fontSizeDelta == 0.0f);
-            D.assert(letterSpacing != null || (letterSpacingFactor == 1.0f && letterSpacingDelta == 0.0f));
-            D.assert(wordSpacing != null || (wordSpacingFactor == 1.0f && wordSpacingDelta == 0.0f));
-            D.assert(height != null || (heightFactor == 1.0f && heightDelta == 0.0f));
+            D.assert(letterSpacing != null || letterSpacingFactor == 1.0f && letterSpacingDelta == 0.0f);
+            D.assert(wordSpacing != null || wordSpacingFactor == 1.0f && wordSpacingDelta == 0.0f);
+            D.assert(height != null || heightFactor == 1.0f && heightDelta == 0.0f);
-                     (decorationThicknessFactor == 1.0f && decorationThicknessDelta == 0.0f));
+                     decorationThicknessFactor == 1.0f && decorationThicknessDelta == 0.0f);
-            string modifiedDebugLabel = "";
+            var modifiedDebugLabel = "";
             D.assert(() => {
                 if (debugLabel != null) {
                     modifiedDebugLabel = debugLabel + ".apply";
 
             return new TextStyle(
                 inherit: inherit,
-                color: foreground == null ? color ?? this.color : null,
-                backgroundColor: background == null ? backgroundColor ?? this.backgroundColor : null,
+                foreground == null ? color ?? this.color : null,
+                background == null ? backgroundColor ?? this.backgroundColor : null,
                 fontFamily: fontFamily ?? this.fontFamily,
                 fontFamilyFallback: fontFamilyFallback ?? this.fontFamilyFallback,
                 fontSize: fontSize == null ? null : fontSize * fontSizeFactor + fontSizeDelta,
             });
 
             return new TextStyle(
-                inherit: inherit ?? this.inherit,
-                color: this.foreground == null && foreground == null ? color ?? this.color : null,
-                backgroundColor: this.background == null && background == null ? backgroundColor ?? this.backgroundColor : null,
+                inherit ?? this.inherit,
+                this.foreground == null && foreground == null ? color ?? this.color : null,
+                this.background == null && background == null ? backgroundColor ?? this.backgroundColor : null,
                 fontFamily: fontFamily ?? this.fontFamily,
                 fontFamilyFallback: fontFamilyFallback ?? this.fontFamilyFallback,
                 fontSize: fontSize ?? this.fontSize,
                 return null;
             }
 
-            string lerpDebugLabel = "";
+            var lerpDebugLabel = "";
             D.assert(() => {
                 lerpDebugLabel = "lerp" + (a?.debugLabel ?? _kDefaultDebugLabel) + "-" + t + "-" +
                                  (b?.debugLabel ?? _kDefaultDebugLabel);
             if (a == null) {
                 return new TextStyle(
                     inherit: b.inherit,
-                    color: Color.lerp(null, b.color, t),
-                    backgroundColor: Color.lerp(null, b.backgroundColor, t),
+                    Color.lerp(null, b: b.color, t: t),
+                    Color.lerp(null, b: b.backgroundColor, t: t),
                     fontFamily: t < 0.5f ? null : b.fontFamily,
                     fontFamilyFallback: t < 0.5f ? null : b.fontFamilyFallback,
                     fontSize: t < 0.5f ? null : b.fontSize,
                     foreground: t < 0.5f ? null : b.foreground,
                     background: t < 0.5f ? null : b.background,
                     decoration: t < 0.5f ? null : b.decoration,
-                    decorationColor: Color.lerp(null, b.decorationColor, t),
+                    decorationColor: Color.lerp(null, b: b.decorationColor, t: t),
                     decorationStyle: t < 0.5f ? null : b.decorationStyle,
                     decorationThickness: t < 0.5f ? null : b.decorationThickness,
                     shadows: t < 0.5f ? null : b.shadows,
             if (b == null) {
                 return new TextStyle(
                     inherit: a.inherit,
-                    color: Color.lerp(a.color, null, t),
-                    backgroundColor: Color.lerp(a.backgroundColor, null, t),
+                    Color.lerp(a: a.color, null, t: t),
+                    Color.lerp(a: a.backgroundColor, null, t: t),
                     fontFamily: t < 0.5f ? a.fontFamily : null,
                     fontFamilyFallback: t < 0.5f ? a.fontFamilyFallback : null,
                     fontSize: t < 0.5f ? a.fontSize : null,
                     foreground: t < 0.5f ? a.foreground : null,
                     background: t < 0.5f ? a.background : null,
                     decoration: t < 0.5f ? a.decoration : null,
-                    decorationColor: Color.lerp(a.decorationColor, null, t),
+                    decorationColor: Color.lerp(a: a.decorationColor, null, t: t),
                     decorationStyle: t < 0.5f ? a.decorationStyle : null,
                     decorationThickness: t < 0.5f ? a.decorationThickness : null,
                     shadows: t < 0.5f ? a.shadows : null,
 
             return new TextStyle(
                 inherit: b.inherit,
-                color: a.foreground == null && b.foreground == null ? Color.lerp(a.color, b.color, t) : null,
-                backgroundColor: a.background == null && b.background == null
-                    ? Color.lerp(a.backgroundColor, b.backgroundColor, t)
+                a.foreground == null && b.foreground == null ? Color.lerp(a: a.color, b: b.color, t: t) : null,
+                a.background == null && b.background == null
+                    ? Color.lerp(a: a.backgroundColor, b: b.backgroundColor, t: t)
-                fontSize: MathUtils.lerpNullableFloat(a.fontSize ?? b.fontSize, b.fontSize ?? a.fontSize, t),
+                fontSize: MathUtils.lerpNullableFloat(a.fontSize ?? b.fontSize, b.fontSize ?? a.fontSize, t: t),
-                    b.letterSpacing ?? a.letterSpacing, t),
+                    b.letterSpacing ?? a.letterSpacing, t: t),
-                    b.wordSpacing ?? a.wordSpacing, t),
+                    b.wordSpacing ?? a.wordSpacing, t: t),
-                height: MathUtils.lerpNullableFloat(a.height ?? b.height, b.height ?? a.height, t),
-                foreground: (a.foreground != null || b.foreground != null)
+                height: MathUtils.lerpNullableFloat(a.height ?? b.height, b.height ?? a.height, t: t),
+                foreground: a.foreground != null || b.foreground != null
-                        ? a.foreground ?? new Paint() {color = a.color}
-                        : b.foreground ?? new Paint() {color = b.color}
+                        ? a.foreground ?? new Paint {color = a.color}
+                        : b.foreground ?? new Paint {color = b.color}
-                background: (a.background != null || b.background != null)
+                background: a.background != null || b.background != null
-                        ? a.background ?? new Paint() {color = a.backgroundColor}
-                        : b.background ?? new Paint() {color = b.backgroundColor}
+                        ? a.background ?? new Paint {color = a.backgroundColor}
+                        : b.background ?? new Paint {color = b.backgroundColor}
-                decorationColor: Color.lerp(a.decorationColor, b.decorationColor, t),
+                decorationColor: Color.lerp(a: a.decorationColor, b: b.decorationColor, t: t),
-                    b.decorationThickness ?? a.decorationThickness ?? 0.0f, t),
+                    b.decorationThickness ?? a.decorationThickness ?? 0.0f, t: t),
                 shadows: t < 0.5f ? a.shadows : b.shadows,
                 fontFeatures: t < 0.5 ? a.fontFeatures : b.fontFeatures,
                 debugLabel: lerpDebugLabel
-        ui.ParagraphStyle getParagraphStyle(
+        ParagraphStyle getParagraphStyle(
-            ui.TextHeightBehavior textHeightBehavior = null,
+            TextHeightBehavior textHeightBehavior = null,
             Locale locale = null,
             string fontFamily = null,
             float? fontSize = null,
             StrutStyle strutStyle = null
         ) {
             D.assert(maxLines == null || maxLines > 0);
-            return new ui.ParagraphStyle(
+            return new ParagraphStyle(
-                textDirection: textDirection,
+                textDirection ?? TextDirection.ltr,
                 fontWeight: fontWeight ?? this.fontWeight,
                 fontStyle: fontStyle ?? this.fontStyle,
                 fontFamily: fontFamily ?? this.fontFamily,
                     : new ui.StrutStyle(
                         fontFamily: strutStyle.fontFamily,
                         fontFamilyFallback: strutStyle.fontFamilyFallback,
-                        fontSize: strutStyle.fontSize == null ? null : strutStyle.fontSize * textScaleFactor,
+                        strutStyle.fontSize == null ? null : strutStyle.fontSize * textScaleFactor,
                         height: strutStyle.height,
                         leading: strutStyle.leading,
                         fontWeight: strutStyle.fontWeight,
                 textBaseline: textBaseline,
                 fontFamily: fontFamily,
                 fontFamilyFallback: fontFamilyFallback,
-                fontSize: fontSize == null ? null : fontSize * textScaleFactor,
+                fontSize == null ? null : fontSize * textScaleFactor,
                 letterSpacing: letterSpacing,
                 wordSpacing: wordSpacing,
                 height: height,
             );
         }
 
-        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) { 
-            debugFillProperties(properties, "");
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            debugFillProperties(properties: properties);
-            base.debugFillProperties(properties);
+            base.debugFillProperties(properties: properties);
-            List<DiagnosticsNode> styles = new List<DiagnosticsNode>();
-            styles.Add(new ColorProperty($"{prefix}color", color,
+            var styles = new List<DiagnosticsNode>();
+            styles.Add(new ColorProperty($"{prefix}color", value: color,
-            styles.Add(new ColorProperty($"{prefix}backgroundColor", backgroundColor,
+            styles.Add(new ColorProperty($"{prefix}backgroundColor", value: backgroundColor,
-            styles.Add(new StringProperty($"{prefix}family", fontFamily, defaultValue: foundation_.kNullDefaultValue,
+            styles.Add(new StringProperty($"{prefix}family", value: fontFamily,
+                defaultValue: foundation_.kNullDefaultValue,
-            styles.Add(new EnumerableProperty<string>($"{prefix}familyFallback", fontFamilyFallback,
+            styles.Add(new EnumerableProperty<string>($"{prefix}familyFallback", value: fontFamilyFallback,
-            styles.Add(new DiagnosticsProperty<float?>($"{prefix}size", fontSize,
+            styles.Add(new DiagnosticsProperty<float?>($"{prefix}size", value: fontSize,
-            string weightDescription = "";
+            var weightDescription = "";
-                "weight", fontWeight,
+                "weight", value: fontWeight,
-            styles.Add(new EnumProperty<FontStyle?>($"{prefix}style", fontStyle,
+            styles.Add(new EnumProperty<FontStyle?>($"{prefix}style", value: fontStyle,
-            styles.Add(new DiagnosticsProperty<float?>($"{prefix}letterSpacing", letterSpacing,
+            styles.Add(new DiagnosticsProperty<float?>($"{prefix}letterSpacing", value: letterSpacing,
-            styles.Add(new DiagnosticsProperty<float?>($"{prefix}wordSpacing", wordSpacing,
+            styles.Add(new DiagnosticsProperty<float?>($"{prefix}wordSpacing", value: wordSpacing,
-            styles.Add(new EnumProperty<TextBaseline?>($"{prefix}baseline", textBaseline,
+            styles.Add(new EnumProperty<TextBaseline?>($"{prefix}baseline", value: textBaseline,
-            styles.Add(new DiagnosticsProperty<float?>($"{prefix}height", height,
+            styles.Add(new DiagnosticsProperty<float?>($"{prefix}height", value: height,
                 defaultValue: foundation_.kNullDefaultValue));
             styles.Add(new StringProperty($"{prefix}foreground", foreground == null ? null : foreground.ToString(),
                 defaultValue: foundation_.kNullDefaultValue, quoted: false));
-                List<string> decorationDescription = new List<string>();
+                var decorationDescription = new List<string>();
-                styles.Add(new ColorProperty($"{prefix}decorationColor", decorationColor,
+                styles.Add(new ColorProperty($"{prefix}decorationColor", value: decorationColor,
                     defaultValue: foundation_.kNullDefaultValue,
                     level: DiagnosticLevel.fine));
                 if (decorationColor != null) {
-                styles.Add(new DiagnosticsProperty<TextDecoration>($"{prefix}decoration", decoration,
+                styles.Add(new DiagnosticsProperty<TextDecoration>($"{prefix}decoration", value: decoration,
                     defaultValue: foundation_.kNullDefaultValue,
                     level: DiagnosticLevel.hidden));
                 if (decoration != null) {
-                D.assert(decorationDescription.isNotEmpty);
-                styles.Add(new MessageProperty($"{prefix}decoration", string.Join(" ", decorationDescription.ToArray())));
-                styles.Add(new FloatProperty($"{prefix}decorationThickness", decorationThickness, unit: "x",
+                D.assert(result: decorationDescription.isNotEmpty);
+                styles.Add(
+                    new MessageProperty($"{prefix}decoration", string.Join(" ", decorationDescription.ToArray())));
+                styles.Add(new FloatProperty($"{prefix}decorationThickness", value: decorationThickness, unit: "x",
-            bool styleSpecified = styles.Any((DiagnosticsNode n) => !n.isFiltered(DiagnosticLevel.info));
-            properties.add(new DiagnosticsProperty<bool>("inherit", inherit,
-                level: (!styleSpecified && inherit) ? DiagnosticLevel.fine : DiagnosticLevel.info));
+            var styleSpecified = styles.Any(n => !n.isFiltered(minLevel: DiagnosticLevel.info));
+            properties.add(new DiagnosticsProperty<bool>("inherit", value: inherit,
+                level: !styleSpecified && inherit ? DiagnosticLevel.fine : DiagnosticLevel.info));
-                properties.add(style);
+                properties.add(property: style);
-                properties.add(new FlagProperty("inherit", value: inherit, ifTrue: $"{prefix}<all styles inherited>",
-                    ifFalse: $"{prefix}<no style specified>"));
+                properties.add(new FlagProperty("inherit", value: inherit, $"{prefix}<all styles inherited>",
+                    $"{prefix}<no style specified>"));
-        public bool Equals(TextStyle other) {
-            if (ReferenceEquals(null, other)) {
-                return false;
-            }
-
-            if (ReferenceEquals(this, other)) {
-                return true;
-            }
-
-            return inherit == other.inherit &&
-                   Equals(color, other.color) &&
-                   Equals(backgroundColor, other.backgroundColor) &&
-                   fontSize.Equals(other.fontSize) &&
-                   fontWeight == other.fontWeight &&
-                   fontStyle == other.fontStyle &&
-                   letterSpacing.Equals(other.letterSpacing) &&
-                   wordSpacing.Equals(other.wordSpacing) &&
-                   textBaseline == other.textBaseline &&
-                   height.Equals(other.height) &&
-                   Equals(decoration, other.decoration) &&
-                   Equals(decorationColor, other.decorationColor) &&
-                   decorationStyle == other.decorationStyle &&
-                   decorationThickness == other.decorationThickness &&
-                   Equals(foreground, other.foreground) &&
-                   Equals(background, other.background) &&
-                   fontFamilyFallback.equalsList(other.fontFamilyFallback) &&
-                   shadows.equalsList(other.shadows) &&
-                   fontFeatures.equalsList(other.fontFeatures) &&
-                   string.Equals(fontFamily, other.fontFamily);
-        }
-
-            if (ReferenceEquals(null, obj)) {
+            if (ReferenceEquals(null, objB: obj)) {
-            if (ReferenceEquals(this, obj)) {
+            if (ReferenceEquals(this, objB: obj)) {
                 return true;
             }
 
         }
 
         public static bool operator ==(TextStyle left, TextStyle right) {
-            return Equals(left, right);
+            return Equals(objA: left, objB: right);
-            return !Equals(left, right);
+            return !Equals(objA: left, objB: right);
         }
 
         public override string toStringShort() {

com.unity.uiwidgets/Runtime/rendering/sliver_multi_box_adaptor.cs

 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.painting;
                     trailingGarbage -= 1;
                 }
 
-                _keepAliveBucket.Values.Where(child => {
+                LinqUtils<RenderBox>.WhereList(_keepAliveBucket.Values, (child => {
-                }).ToList().ForEach(_childManager.removeChild);
+                })).ForEach(_childManager.removeChild);
-                D.assert(_keepAliveBucket.Values.Where(child => {
+                D.assert(LinqUtils<RenderBox>.WhereList(_keepAliveBucket.Values, (child => {
-                }).ToList().isEmpty());
+                })).isEmpty());
             });
         }
 

com.unity.uiwidgets/Runtime/scheduler2/binding.cs

 using developer;
 using Unity.UIWidgets.async;
 using Unity.UIWidgets.async2;
+using Unity.UIWidgets.engine2;
-using Timer = Unity.UIWidgets.async2.Timer;
+        static float _timeDilation = 1.0f;
+
-                if (_timeDilation == value)
+                if (_timeDilation == value) {
+                }
-
-        static float _timeDilation = 1.0f;
     }
 
     public delegate void FrameCallback(TimeSpan timeStamp);
     }
 
     class _TaskEntry<T> : _TaskEntry {
+        public readonly TaskCallback<T> task;
+        public Completer completer;
+
         internal _TaskEntry(TaskCallback<T> task, int priority) {
             this.task = task;
             this.priority = priority;
             completer = Completer.create();
         }
 
-        public readonly TaskCallback<T> task;
-        public Completer completer;
 
         public void run() {
             if (!foundation_.kReleaseMode) {
         }
 
         public int CompareTo(_TaskEntry other) {
-            return -priority.CompareTo(other.priority);
+            return -priority.CompareTo(value: other.priority);
+        public static string debugCurrentCallbackStack;
+
+        public readonly FrameCallback callback;
+        public string debugStack;
+
         internal _FrameCallbackEntry(FrameCallback callback, bool rescheduling = false) {
             this.callback = callback;
 
                         if (debugCurrentCallbackStack == null) {
                             throw new UIWidgetsError(
-                                new List<DiagnosticsNode>() {
+                                new List<DiagnosticsNode> {
                                     new ErrorSummary(
                                         "scheduleFrameCallback called with rescheduling true, but no callback is in scope."),
                                     new ErrorDescription(
                 return true;
             });
         }
-
-        public readonly FrameCallback callback;
-
-        public static string debugCurrentCallbackStack;
-        public string debugStack;
     }
 
     public enum SchedulerPhase {
         persistentCallbacks,
-        postFrameCallbacks,
+        postFrameCallbacks
+        readonly List<FrameCallback> _persistentCallbacks = new List<FrameCallback>();
+
+        readonly List<FrameCallback> _postFrameCallbacks = new List<FrameCallback>();
+        readonly HashSet<int> _removedIds = new HashSet<int>();
+
+        readonly PriorityQueue<_TaskEntry> _taskQueue = new PriorityQueue<_TaskEntry>();
+
+        readonly List<TimingsCallback> _timingsCallbacks = new List<TimingsCallback>();
+
+        TimeSpan? _currentFrameTimeStamp;
+        string _debugBanner;
+
+        int _debugFrameNumber;
+        TimeSpan _epochStart = TimeSpan.Zero;
+
+        TimeSpan? _firstRawTimeStampInEpoch;
+
+        bool _hasRequestedAnEventLoopCallback;
+        bool _ignoreNextEngineDrawFrame;
+
+        int _nextFrameCallbackId;
+
+        Completer _nextFrameCompleter;
+        Dictionary<int, _FrameCallbackEntry> _transientCallbacks = new Dictionary<int, _FrameCallbackEntry>();
+
+        bool _warmUpFrame;
+
+
+        public SchedulingStrategy schedulingStrategy = scheduler_.defaultSchedulingStrategy;
+
+        public static SchedulerBinding instance {
+            get { return (SchedulerBinding) Window.instance._binding; }
+            private set { Window.instance._binding = value; }
+        }
+
+        public AppLifecycleState? lifecycleState { get; private set; }
+
+        public int transientCallbackCount {
+            get { return _transientCallbacks.Count; }
+        }
+
+        public Future endOfFrame {
+            get {
+                if (_nextFrameCompleter == null) {
+                    if (schedulerPhase == SchedulerPhase.idle) {
+                        scheduleFrame();
+                    }
+
+                    _nextFrameCompleter = Completer.create();
+                    addPostFrameCallback(timeStamp => {
+                        _nextFrameCompleter.complete();
+                        _nextFrameCompleter = null;
+                    });
+                }
+
+                return _nextFrameCompleter.future;
+            }
+        }
+
+        public bool hasScheduledFrame { get; private set; }
+
+        public SchedulerPhase schedulerPhase { get; private set; } = SchedulerPhase.idle;
+
+        public bool framesEnabled { get; private set; } = true;
+
+        public TimeSpan currentFrameTimeStamp {
+            get {
+                D.assert(_currentFrameTimeStamp != null);
+                return _currentFrameTimeStamp.Value;
+            }
+        }
+
+        public TimeSpan currentSystemFrameTimeStamp { get; private set; } = TimeSpan.Zero;
+
         protected override void initInstances() {
             base.initInstances();
             instance = this;
 
             if (!foundation_.kReleaseMode) {
-                int frameNumber = 0;
-                addTimingsCallback((List<FrameTiming> timings) => {
-                    foreach (FrameTiming frameTiming in timings) {
+                var frameNumber = 0;
+                addTimingsCallback(timings => {
+                    foreach (var frameTiming in timings) {
-                        _profileFramePostEvent(frameNumber, frameTiming);
+                        _profileFramePostEvent(frameNumber: frameNumber, frameTiming: frameTiming);
-        readonly List<TimingsCallback> _timingsCallbacks = new List<TimingsCallback>();
-
-            _timingsCallbacks.Add(callback);
+            _timingsCallbacks.Add(item: callback);
             if (_timingsCallbacks.Count == 1) {
                 D.assert(window.onReportTimings == null);
                 window.onReportTimings = _executeTimingsCallbacks;
         }
 
         public void removeTimingsCallback(TimingsCallback callback) {
-            D.assert(_timingsCallbacks.Contains(callback));
-            _timingsCallbacks.Remove(callback);
+            D.assert(_timingsCallbacks.Contains(item: callback));
+            _timingsCallbacks.Remove(item: callback);
             if (_timingsCallbacks.isEmpty()) {
                 window.onReportTimings = null;
             }
-            List<TimingsCallback> clonedCallbacks =
-                new List<TimingsCallback>(_timingsCallbacks);
-            foreach (TimingsCallback callback in clonedCallbacks) {
+            var clonedCallbacks =
+                new List<TimingsCallback>(collection: _timingsCallbacks);
+            foreach (var callback in clonedCallbacks) {
-                    if (_timingsCallbacks.Contains(callback)) {
-                        callback(timings);
+                    if (_timingsCallbacks.Contains(item: callback)) {
+                        callback(timings: timings);
                     }
                 }
                 catch (Exception ex) {
                             yield return new DiagnosticsProperty<TimingsCallback>(
                                 "The TimingsCallback that gets executed was",
-                                callback,
+                                value: callback,
+
                         collector = infoCollect;
                         return true;
                     });
             }
         }
 
-        public static SchedulerBinding instance {
-            get { return (SchedulerBinding) Window.instance._binding; }
-            private set { Window.instance._binding = value; }
-        }
-
-        public AppLifecycleState? lifecycleState => _lifecycleState;
-        AppLifecycleState? _lifecycleState;
-
-            if (_lifecycleState == null) {
-                handleAppLifecycleStateChanged(_parseAppLifecycleMessage(window.initialLifecycleState));
+            if (lifecycleState == null) {
+                handleAppLifecycleStateChanged(_parseAppLifecycleMessage(message: window.initialLifecycleState));
-            _lifecycleState = state;
+            lifecycleState = state;
             switch (state) {
                 case AppLifecycleState.resumed:
                 case AppLifecycleState.inactive:
             throw new Exception("unknown AppLifecycleState: " + message);
         }
 
-
-        public SchedulingStrategy schedulingStrategy = scheduler_.defaultSchedulingStrategy;
-
-        readonly PriorityQueue<_TaskEntry> _taskQueue = new PriorityQueue<_TaskEntry>();
-
-            bool isFirstTask = _taskQueue.isEmpty;
-            _TaskEntry<T> entry = new _TaskEntry<T>(
-                task,
-                priority.value
+            var isFirstTask = _taskQueue.isEmpty;
+            var entry = new _TaskEntry<T>(
+                task: task,
+                priority: priority.value
-            _taskQueue.enqueue(entry);
-            if (isFirstTask && !locked)
+            _taskQueue.enqueue(item: entry);
+            if (isFirstTask && !locked) {
+            }
+
-        
+
-            if (_taskQueue.isNotEmpty)
+            if (_taskQueue.isNotEmpty) {
+            }
-        bool _hasRequestedAnEventLoopCallback = false;
-
-            D.assert(!locked);
+            D.assert(result: !locked);
-            if (_hasRequestedAnEventLoopCallback)
+            if (_hasRequestedAnEventLoopCallback) {
+            }
+
-            Timer.run(_runTasks);
+            Timer.run(callback: _runTasks);
-            if (handleEventLoopCallback())
+            if (handleEventLoopCallback()) {
+            }
+
-            if (_taskQueue.isEmpty || locked)
+            if (_taskQueue.isEmpty || locked) {
+            }
-            _TaskEntry entry = _taskQueue.first;
-            if (schedulingStrategy(priority: entry.priority, scheduler: this)) {
+            var entry = _taskQueue.first;
+            if (schedulingStrategy(priority: entry.priority, this)) {
                 try {
                     _taskQueue.removeFirst();
                     entry.run();
                     });
 
                     IEnumerable<DiagnosticsNode> infoCollector() {
-                        yield return DiagnosticsNode.message("\nThis exception was thrown in the context of a scheduler callback. " +
-                                                             "When the scheduler callback was _registered_ (as opposed to when the " +
-                                                             "exception was thrown), this was the stack: " + callbackStack);
+                        yield return DiagnosticsNode.message(
+                            "\nThis exception was thrown in the context of a scheduler callback. " +
+                            "When the scheduler callback was _registered_ (as opposed to when the " +
+                            "exception was thrown), this was the stack: " + callbackStack);
-                    
+
-                        library: "scheduler library",
-                        context: new ErrorDescription("during a task callback"),
+                        "scheduler library",
+                        new ErrorDescription("during a task callback"),
                         informationCollector: callbackStack == null
                             ? (InformationCollector) null
                             : infoCollector
 
             return false;
         }
-
-        int _nextFrameCallbackId = 0;
-        Dictionary<int, _FrameCallbackEntry> _transientCallbacks = new Dictionary<int, _FrameCallbackEntry>();
-        readonly HashSet<int> _removedIds = new HashSet<int>();
-
-        public int transientCallbackCount => _transientCallbacks.Count;
-            _transientCallbacks[_nextFrameCallbackId] =
-                new _FrameCallbackEntry(callback, rescheduling: rescheduling);
+            _transientCallbacks[key: _nextFrameCallbackId] =
+                new _FrameCallbackEntry(callback: callback, rescheduling: rescheduling);
-            _transientCallbacks.Remove(id);
-            _removedIds.Add(id);
+            _transientCallbacks.Remove(key: id);
+            _removedIds.Add(item: id);
-
-        readonly List<FrameCallback> _persistentCallbacks = new List<FrameCallback>();
-            _persistentCallbacks.Add(callback);
+            _persistentCallbacks.Add(item: callback);
-        readonly List<FrameCallback> _postFrameCallbacks = new List<FrameCallback>();
-
-            _postFrameCallbacks.Add(callback);
+            _postFrameCallbacks.Add(item: callback);
-        Completer _nextFrameCompleter;
-
-        public Future endOfFrame {
-            get {
-                if (_nextFrameCompleter == null) {
-                    if (schedulerPhase == SchedulerPhase.idle)
-                        scheduleFrame();
-                    _nextFrameCompleter = Completer.create();
-                    addPostFrameCallback((timeStamp) => {
-                        _nextFrameCompleter.complete();
-                        _nextFrameCompleter = null;
-                    });
-                }
-
-                return _nextFrameCompleter.future;
+        void _setFramesEnabledState(bool enabled) {
+            if (framesEnabled == enabled) {
+                return;
-        }
-
-        public bool hasScheduledFrame => _hasScheduledFrame;
-        bool _hasScheduledFrame = false;
-
-        public SchedulerPhase schedulerPhase => _schedulerPhase;
-        SchedulerPhase _schedulerPhase = SchedulerPhase.idle;
-        public bool framesEnabled => _framesEnabled;
-        bool _framesEnabled = true;
-
-        void _setFramesEnabledState(bool enabled) {
-            if (_framesEnabled == enabled)
-                return;
-            _framesEnabled = enabled;
-            if (enabled)
+            framesEnabled = enabled;
+            if (enabled) {
+            }
         }
 
         protected void ensureFrameCallbacksRegistered() {
         }
 
         public void scheduleFrame() {
-            if (_hasScheduledFrame || !framesEnabled)
+            if (hasScheduledFrame || !framesEnabled) {
+            }
 
             D.assert(() => {
                 if (scheduler_.debugPrintScheduleFrameStacks) {
 
             ensureFrameCallbacksRegistered();
             Window.instance.scheduleFrame();
-            _hasScheduledFrame = true;
+            hasScheduledFrame = true;
-            if (!framesEnabled)
+            if (!framesEnabled) {
+            }
-            if (_hasScheduledFrame)
+            if (hasScheduledFrame) {
+            }
 
             D.assert(() => {
                 if (scheduler_.debugPrintScheduleFrameStacks) {
 
             ensureFrameCallbacksRegistered();
             Window.instance.scheduleFrame();
-            _hasScheduledFrame = true;
+            hasScheduledFrame = true;
-        bool _warmUpFrame = false;
-
-            if (_warmUpFrame || schedulerPhase != SchedulerPhase.idle)
+            if (_warmUpFrame || schedulerPhase != SchedulerPhase.idle) {
+            }
-            bool hadScheduledFrame = _hasScheduledFrame;
+            var hadScheduledFrame = hasScheduledFrame;
-                D.assert(_warmUpFrame);
+                D.assert(result: _warmUpFrame);
-                D.assert(_warmUpFrame);
+                D.assert(result: _warmUpFrame);
                 handleDrawFrame();
                 // We call resetEpoch after this frame so that, in the hot reload case,
                 // the very next frame pretends to have occurred immediately after this
                 // then skipping every frame and finishing in the new time.
                 resetEpoch();
                 _warmUpFrame = false;
-                if (hadScheduledFrame)
+                if (hadScheduledFrame) {
+                }
+
                 return null;
             });
 
             }));
         }
 
-        TimeSpan? _firstRawTimeStampInEpoch;
-        TimeSpan _epochStart = TimeSpan.Zero;
-        TimeSpan _lastRawTimeStamp = TimeSpan.Zero;
-
-            _epochStart = _adjustForEpoch(_lastRawTimeStamp);
+            _epochStart = _adjustForEpoch(rawTimeStamp: currentSystemFrameTimeStamp);
             _firstRawTimeStampInEpoch = null;
         }
 
                                 _epochStart.Ticks);
         }
 
-        public TimeSpan currentFrameTimeStamp {
-            get {
-                D.assert(_currentFrameTimeStamp != null);
-                return _currentFrameTimeStamp.Value;
-            }
-        }
-
-        TimeSpan? _currentFrameTimeStamp;
-
-        public TimeSpan currentSystemFrameTimeStamp => _lastRawTimeStamp;
-
-        int _debugFrameNumber = 0;
-        string _debugBanner;
-        bool _ignoreNextEngineDrawFrame = false;
-
-                D.assert(!_ignoreNextEngineDrawFrame);
+                D.assert(result: !_ignoreNextEngineDrawFrame);
-            handleBeginFrame(rawTimeStamp);
+            handleBeginFrame(rawTimeStamp: rawTimeStamp);
         }
 
         void _handleDrawFrame() {
 
         public void handleBeginFrame(TimeSpan? rawTimeStamp) {
             Timeline.startSync("Frame");
-
-            _currentFrameTimeStamp = _adjustForEpoch(rawTimeStamp ?? _lastRawTimeStamp);
+            _currentFrameTimeStamp = _adjustForEpoch(rawTimeStamp ?? currentSystemFrameTimeStamp);
-            if (rawTimeStamp != null)
-                _lastRawTimeStamp = rawTimeStamp.Value;
+            if (rawTimeStamp != null) {
+                currentSystemFrameTimeStamp = rawTimeStamp.Value;
+            }
-                    StringBuilder frameTimeStampDescription = new StringBuilder();
+                    var frameTimeStampDescription = new StringBuilder();
-                        _debugDescribeTimeStamp(_currentFrameTimeStamp.Value, frameTimeStampDescription);
+                        _debugDescribeTimeStamp(timeStamp: _currentFrameTimeStamp.Value,
+                            buffer: frameTimeStampDescription);
                     }
                     else {
                         frameTimeStampDescription.Append("(warm-up frame)");
                         $"▄▄▄▄▄▄▄▄ Frame {_debugFrameNumber.ToString().PadRight(7)}   ${frameTimeStampDescription.ToString().PadLeft(18)} ▄▄▄▄▄▄▄▄";
-                    if (scheduler_.debugPrintBeginFrameBanner)
-                        Debug.Log(_debugBanner);
+                    if (scheduler_.debugPrintBeginFrameBanner) {
+                        Debug.Log(message: _debugBanner);
+                    }
-            D.assert(_schedulerPhase == SchedulerPhase.idle);
-            _hasScheduledFrame = false;
+            D.assert(schedulerPhase == SchedulerPhase.idle);
+            hasScheduledFrame = false;
-                _schedulerPhase = SchedulerPhase.transientCallbacks;
+                schedulerPhase = SchedulerPhase.transientCallbacks;
-                    if (!_removedIds.Contains(entry.Key)) {
+                    if (!_removedIds.Contains(item: entry.Key)) {
-                            entry.Value.callback, _currentFrameTimeStamp.Value, entry.Value.debugStack);
+                            callback: entry.Value.callback, timeStamp: _currentFrameTimeStamp.Value,
+                            callbackStack: entry.Value.debugStack);
                     }
                 }
 
-                _schedulerPhase = SchedulerPhase.midFrameMicrotasks;
+                schedulerPhase = SchedulerPhase.midFrameMicrotasks;
-            D.assert(_schedulerPhase == SchedulerPhase.midFrameMicrotasks);
+            
+            D.assert(schedulerPhase == SchedulerPhase.midFrameMicrotasks);
-
-                _schedulerPhase = SchedulerPhase.persistentCallbacks;
-                foreach (FrameCallback callback in _persistentCallbacks)
-                    _invokeFrameCallback(callback, _currentFrameTimeStamp.Value);
+                schedulerPhase = SchedulerPhase.persistentCallbacks;
+                foreach (var callback in _persistentCallbacks) {
+                    _invokeFrameCallback(callback: callback, timeStamp: _currentFrameTimeStamp.Value);
+                }
-                _schedulerPhase = SchedulerPhase.postFrameCallbacks;
-                var localPostFrameCallbacks = new List<FrameCallback>(_postFrameCallbacks);
+                schedulerPhase = SchedulerPhase.postFrameCallbacks;
+                var localPostFrameCallbacks = new List<FrameCallback>(collection: _postFrameCallbacks);
-                foreach (FrameCallback callback in localPostFrameCallbacks)
-                    _invokeFrameCallback(callback, _currentFrameTimeStamp.Value);
+                foreach (var callback in localPostFrameCallbacks) {
+                    _invokeFrameCallback(callback: callback, timeStamp: _currentFrameTimeStamp.Value);
+                }
-                _schedulerPhase = SchedulerPhase.idle;
+                schedulerPhase = SchedulerPhase.idle;
-                    if (scheduler_.debugPrintEndFrameBanner)
-                        Debug.Log(new string('▀', _debugBanner.Length));
+                    if (scheduler_.debugPrintEndFrameBanner) {
+                        Debug.Log(new string('▀', count: _debugBanner.Length));
+                    }
+
                     _debugBanner = null;
                     return true;
                 });
         void _profileFramePostEvent(int frameNumber, FrameTiming frameTiming) {
             developer_.postEvent("Flutter.Frame", new Hashtable {
                 {"number", frameNumber},
-                {"startTime", frameTiming.timestampInMicroseconds(FramePhase.buildStart)},
+                {"startTime", frameTiming.timestampInMicroseconds(phase: FramePhase.buildStart)},
-                {"raster", (int) (frameTiming.rasterDuration.TotalMilliseconds * 1000)},
+                {"raster", (int) (frameTiming.rasterDuration.TotalMilliseconds * 1000)}
-            if (timeStamp.TotalDays > 0)
-                buffer.AppendFormat("{0}d ", timeStamp.Days);
-            if (timeStamp.TotalHours > 0)
-                buffer.AppendFormat("{0}h ", timeStamp.Hours);
-            if (timeStamp.TotalMinutes > 0)
-                buffer.AppendFormat("{0}m ", timeStamp.Minutes);
-            if (timeStamp.TotalSeconds > 0)
-                buffer.AppendFormat("{0}s ", timeStamp.Seconds);
-            buffer.AppendFormat("{0}", timeStamp.Milliseconds);
+            if (timeStamp.TotalDays > 0) {
+                buffer.AppendFormat("{0}d ", arg0: timeStamp.Days);
+            }
+
+            if (timeStamp.TotalHours > 0) {
+                buffer.AppendFormat("{0}h ", arg0: timeStamp.Hours);
+            }
+
+            if (timeStamp.TotalMinutes > 0) {
+                buffer.AppendFormat("{0}m ", arg0: timeStamp.Minutes);
+            }
+
+            if (timeStamp.TotalSeconds > 0) {
+                buffer.AppendFormat("{0}s ", arg0: timeStamp.Seconds);
+            }
+
+            buffer.AppendFormat("{0}", arg0: timeStamp.Milliseconds);
-            int microseconds = (int) (timeStamp.Ticks % 10000 / 10);
-            if (microseconds > 0)
+            var microseconds = (int) (timeStamp.Ticks % 10000 / 10);
+            if (microseconds > 0) {
+            }
+
             buffer.Append("ms");
         }
 
             });
 
             try {
-                callback(timeStamp);
+                callback(timeStamp: timeStamp);
-                    yield return DiagnosticsNode.message("\nThis exception was thrown in the context of a scheduler callback. " +
-                                                         "When the scheduler callback was _registered_ (as opposed to when the " +
-                                                         "exception was thrown), this was the stack:");
-                    StringBuilder builder = new StringBuilder();
+                    yield return DiagnosticsNode.message(
+                        "\nThis exception was thrown in the context of a scheduler callback. " +
+                        "When the scheduler callback was _registered_ (as opposed to when the " +
+                        "exception was thrown), this was the stack:");
+                    var builder = new StringBuilder();
-                        builder.AppendLine(line);
+                        builder.AppendLine(value: line);
-                
+
-                    library: "scheduler library",
-                    context: new ErrorDescription("during a scheduler callback"),
+                    "scheduler library",
+                    new ErrorDescription("during a scheduler callback"),
                     informationCollector: callbackStack == null
                         ? (InformationCollector) null
                         : infoCollector
 
     public static partial class scheduler_ {
         public static bool defaultSchedulingStrategy(int priority, SchedulerBinding scheduler) {
-            if (scheduler.transientCallbackCount > 0)
+            if (scheduler.transientCallbackCount > 0) {
+            }
+
             return true;
         }
     }

com.unity.uiwidgets/Runtime/services/asset_bundle.cs

 using System.Collections.Generic;
 using System.Text;
 using Unity.UIWidgets.async2;
-using Unity.UIWidgets.editor2;
 using Unity.UIWidgets.engine2;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;

com.unity.uiwidgets/Runtime/ui2/painting.cs

 using AOT;
 using Unity.UIWidgets.animation;
 using Unity.UIWidgets.async2;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using UnityEngine;
 using Unity.UIWidgets.ui;
                 ? PaintingUtils._encodeColorList(colors)
                 : null;
             ushort[] encodedIndices = indices != null
-                ? indices.Select(i => (ushort) i).ToArray()
+                ? LinqUtils<ushort, int>.SelectArray(indices, (i => (ushort) i))
                 : null;
 
             fixed (float* encodedPositionsPtr = encodedPositions, encodedTextureCoordinatesPtr =

com.unity.uiwidgets/Runtime/ui2/window.cs

 using System.Runtime.InteropServices;
 using AOT;
 using Unity.UIWidgets.async2;
-using Unity.UIWidgets.editor2;
 using Unity.UIWidgets.engine2;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;

com.unity.uiwidgets/Runtime/widgets/DiagnosticableTree.mixin.gen.cs

 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using Unity.UIWidgets.external;
 
 namespace Unity.UIWidgets.foundation {
     public class DiagnosticableTreeMixinChangeNotifier : ChangeNotifier, DiagnosticableTreeMixin {
                 DiagnosticPropertiesBuilder builder = new DiagnosticPropertiesBuilder();
                 debugFillProperties(builder);
                 result.Append(string.Join(joiner,
-                    builder.properties.Where(n => !n.isFiltered(minLevel)).Select(n => n.ToString()).ToArray())
+                    LinqUtils<string,DiagnosticsNode>.SelectList(LinqUtils<DiagnosticsNode>.WhereList(builder.properties, (n => !n.isFiltered(minLevel))),(n => n.ToString())))
                 );
                 shallowString = result.ToString();
                 return true;

com.unity.uiwidgets/Runtime/widgets/DiagnosticableTree.mixin.njk

 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using Unity.UIWidgets.external;
 
 namespace Unity.UIWidgets.foundation {
 {% macro DiagnosticableTreeMixin(with) %}
                 DiagnosticPropertiesBuilder builder = new DiagnosticPropertiesBuilder();
                 debugFillProperties(builder);
                 result.Append(string.Join(joiner,
-                    builder.properties.Where(n => !n.isFiltered(minLevel)).Select(n => n.ToString()).ToArray())
+                    LinqUtils<string,DiagnosticsNode>.SelectList(LinqUtils<DiagnosticsNode>.WhereList(builder.properties, (n => !n.isFiltered(minLevel))),(n => n.ToString())))
                 );
                 shallowString = result.ToString();
                 return true;

com.unity.uiwidgets/Runtime/widgets/DirectionalFocusTraversalPolicy.mixin.gen.cs

 using System.Linq;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
+using Unity.UIWidgets.external;
 
 namespace Unity.UIWidgets.widgets {
     public class DirectionalFocusTraversalPolicyMixinFocusTraversalPolicy : FocusTraversalPolicy, DirectionalFocusTraversalPolicyMixin {
         public override void changedScope(FocusNode node = null, FocusScopeNode oldScope = null) { 
             base.changedScope(node: node, oldScope: oldScope); 
             if (oldScope != null) { 
-                var delEntries = _policyData[oldScope]?.history?.Where((_DirectionalPolicyDataEntry entry)=> { 
+                var delEntries = LinqUtils<_DirectionalPolicyDataEntry>.WhereList( _policyData[oldScope]?.history , ((_DirectionalPolicyDataEntry entry)=> { 
-              }); 
+                })); 
                 foreach (var delEntry in delEntries) {
                   _policyData[oldScope]?.history?.Remove(delEntry);
                 }
             IEnumerable<FocusNode> result = new List<FocusNode>();
             switch (direction) { 
                 case TraversalDirection.left: 
-                    result = sorted.Where((FocusNode node) => node.rect != target && node.rect.center.dx <= target.left); 
+                    result = LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => node.rect != target && node.rect.center.dx <= target.left));
-                    result = sorted.Where((FocusNode node) => node.rect != target && node.rect.center.dx >= target.right);
+                    result = LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => node.rect != target && node.rect.center.dx >= target.right));
                     break;
                 case TraversalDirection.up:
                 case TraversalDirection.down:
             FocusTravesalUtils.mergeSort<FocusNode>(sorted, compare: (FocusNode a, FocusNode b) => a.rect.center.dy.CompareTo(b.rect.center.dy));
             switch (direction) { 
                 case TraversalDirection.up:
-                    return sorted.Where((FocusNode node) => node.rect != target && node.rect.center.dy <= target.top);
+                    return LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => node.rect != target && node.rect.center.dy <= target.top));
-                    return sorted.Where((FocusNode node) => node.rect != target && node.rect.center.dy >= target.bottom);
+                    return LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => node.rect != target && node.rect.center.dy >= target.bottom));
                 case TraversalDirection.left:
                 case TraversalDirection.right:
                     break;
                         nearestScope.traversalDescendants
                     ); 
                     if (focusedScrollable != null && !focusedScrollable.position.atEdge()) { 
-                        IEnumerable<FocusNode> filteredEligibleNodes = eligibleNodes.Where((FocusNode node) => Scrollable.of(node.context) == focusedScrollable); 
+                        IEnumerable<FocusNode> filteredEligibleNodes = LinqUtils<FocusNode>.WhereList(eligibleNodes,((FocusNode node) => Scrollable.of(node.context) == focusedScrollable)); 
                         if (filteredEligibleNodes.Count() !=0) { 
                             eligibleNodes = filteredEligibleNodes; 
                         }
                         sorted = sorted.ToList();
                     }
                     Rect band = Rect.fromLTRB(focusedChild.rect.left, float.NegativeInfinity, focusedChild.rect.right, float.PositiveInfinity);
-                    IEnumerable<FocusNode> inBand = sorted.Where((FocusNode node) => !node.rect.intersect(band).isEmpty);
+                    IEnumerable<FocusNode> inBand = LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => !node.rect.intersect(band).isEmpty));
                     if (inBand.Count() !=0) {
                         found = inBand.First();
                         break;
                 case TraversalDirection.left: 
                     eligibleNodes  = _sortAndFilterHorizontally(direction, focusedChild.rect, nearestScope); 
                     if (focusedScrollable != null && !focusedScrollable.position.atEdge()) { 
-                        IEnumerable<FocusNode> filteredEligibleNodes = eligibleNodes.Where((FocusNode node) => Scrollable.of(node.context) == focusedScrollable); 
+                        IEnumerable<FocusNode> filteredEligibleNodes = LinqUtils<FocusNode>.WhereList(eligibleNodes,((FocusNode node) => Scrollable.of(node.context) == focusedScrollable));
                         if (filteredEligibleNodes.Count()!=0) { 
                             eligibleNodes = filteredEligibleNodes; 
                         } 
                         //sorted = sorted.reversed.toList(); 
                     }
                     band = Rect.fromLTRB(float.NegativeInfinity, focusedChild.rect.top, float.PositiveInfinity, focusedChild.rect.bottom); 
-                    inBand = sorted.Where((FocusNode node) => !node.rect.intersect(band).isEmpty); 
+                    inBand = LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => !node.rect.intersect(band).isEmpty));
                     if (inBand.Count()!=0) {
                         found = inBand.First(); 
                         break; 

com.unity.uiwidgets/Runtime/widgets/DirectionalFocusTraversalPolicy.mixin.njk

 using System.Linq;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
+using Unity.UIWidgets.external;
 
 namespace Unity.UIWidgets.widgets {
 {% macro DirectionalFocusTraversalPolicyMixin(with) %}
         public override void changedScope(FocusNode node = null, FocusScopeNode oldScope = null) { 
             base.changedScope(node: node, oldScope: oldScope); 
             if (oldScope != null) { 
-                var delEntries = _policyData[oldScope]?.history?.Where((_DirectionalPolicyDataEntry entry)=> { 
+                var delEntries = LinqUtils<_DirectionalPolicyDataEntry>.WhereList( _policyData[oldScope]?.history , ((_DirectionalPolicyDataEntry entry)=> { 
-              }); 
+                })); 
                 foreach (var delEntry in delEntries) {
                   _policyData[oldScope]?.history?.Remove(delEntry);
                 }
             IEnumerable<FocusNode> result = new List<FocusNode>();
             switch (direction) { 
                 case TraversalDirection.left: 
-                    result = sorted.Where((FocusNode node) => node.rect != target && node.rect.center.dx <= target.left); 
+                    result = LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => node.rect != target && node.rect.center.dx <= target.left));
-                    result = sorted.Where((FocusNode node) => node.rect != target && node.rect.center.dx >= target.right);
+                    result = LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => node.rect != target && node.rect.center.dx >= target.right));
                     break;
                 case TraversalDirection.up:
                 case TraversalDirection.down:
             FocusTravesalUtils.mergeSort<FocusNode>(sorted, compare: (FocusNode a, FocusNode b) => a.rect.center.dy.CompareTo(b.rect.center.dy));
             switch (direction) { 
                 case TraversalDirection.up:
-                    return sorted.Where((FocusNode node) => node.rect != target && node.rect.center.dy <= target.top);
+                    return LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => node.rect != target && node.rect.center.dy <= target.top));
-                    return sorted.Where((FocusNode node) => node.rect != target && node.rect.center.dy >= target.bottom);
+                    return LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => node.rect != target && node.rect.center.dy >= target.bottom));
                 case TraversalDirection.left:
                 case TraversalDirection.right:
                     break;
                         nearestScope.traversalDescendants
                     ); 
                     if (focusedScrollable != null && !focusedScrollable.position.atEdge()) { 
-                        IEnumerable<FocusNode> filteredEligibleNodes = eligibleNodes.Where((FocusNode node) => Scrollable.of(node.context) == focusedScrollable); 
+                        IEnumerable<FocusNode> filteredEligibleNodes = LinqUtils<FocusNode>.WhereList(eligibleNodes,((FocusNode node) => Scrollable.of(node.context) == focusedScrollable)); 
                         if (filteredEligibleNodes.Count() !=0) { 
                             eligibleNodes = filteredEligibleNodes; 
                         }
                         sorted = sorted.ToList();
                     }
                     Rect band = Rect.fromLTRB(focusedChild.rect.left, float.NegativeInfinity, focusedChild.rect.right, float.PositiveInfinity);
-                    IEnumerable<FocusNode> inBand = sorted.Where((FocusNode node) => !node.rect.intersect(band).isEmpty);
+                    IEnumerable<FocusNode> inBand = LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => !node.rect.intersect(band).isEmpty));
                     if (inBand.Count() !=0) {
                         found = inBand.First();
                         break;
                 case TraversalDirection.left: 
                     eligibleNodes  = _sortAndFilterHorizontally(direction, focusedChild.rect, nearestScope); 
                     if (focusedScrollable != null && !focusedScrollable.position.atEdge()) { 
-                        IEnumerable<FocusNode> filteredEligibleNodes = eligibleNodes.Where((FocusNode node) => Scrollable.of(node.context) == focusedScrollable); 
+                        IEnumerable<FocusNode> filteredEligibleNodes = LinqUtils<FocusNode>.WhereList(eligibleNodes,((FocusNode node) => Scrollable.of(node.context) == focusedScrollable));
                         if (filteredEligibleNodes.Count()!=0) { 
                             eligibleNodes = filteredEligibleNodes; 
                         } 
                         //sorted = sorted.reversed.toList(); 
                     }
                     band = Rect.fromLTRB(float.NegativeInfinity, focusedChild.rect.top, float.PositiveInfinity, focusedChild.rect.bottom); 
-                    inBand = sorted.Where((FocusNode node) => !node.rect.intersect(band).isEmpty); 
+                    inBand = LinqUtils<FocusNode>.WhereList(sorted,((FocusNode node) => !node.rect.intersect(band).isEmpty));
                     if (inBand.Count()!=0) {
                         found = inBand.First(); 
                         break; 

com.unity.uiwidgets/Runtime/widgets/app.cs

 using System.Linq;
 using System.Text;
 using Unity.UIWidgets.async2;
-using Unity.UIWidgets.engine;
-using Unity.UIWidgets.widgets;
 using UnityEngine;
 using Color = Unity.UIWidgets.ui.Color;
 using TextStyle = Unity.UIWidgets.painting.TextStyle;
     public delegate string GenerateAppTitle(BuildContext context);
 
     public delegate PageRoute PageRouteFactory(RouteSettings settings, WidgetBuilder builder);
+
+        public static bool showPerformanceOverlayOverride = false;
+        public static bool debugShowWidgetInspectorOverride = false;
+        public static bool debugAllowBannerOverride = true;
+
+        public static readonly Dictionary<LogicalKeySet, Intent> _defaultShortcuts =
+            new Dictionary<LogicalKeySet, Intent> {
+                // Activation
+                {new LogicalKeySet(key1: LogicalKeyboardKey.enter), new Intent(key: ActivateAction.key)},
+                {new LogicalKeySet(key1: LogicalKeyboardKey.space), new Intent(key: ActivateAction.key)},
+                {new LogicalKeySet(key1: LogicalKeyboardKey.gameButtonA), new Intent(key: ActivateAction.key)},
+
+                // Keyboard traversal.
+                {new LogicalKeySet(key1: LogicalKeyboardKey.tab), new Intent(key: NextFocusAction.key)}, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.shift, key2: LogicalKeyboardKey.tab),
+                    new Intent(key: PreviousFocusAction.key)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowLeft),
+                    new DirectionalFocusIntent(direction: TraversalDirection.left)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowRight),
+                    new DirectionalFocusIntent(direction: TraversalDirection.right)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowDown),
+                    new DirectionalFocusIntent(direction: TraversalDirection.down)
+                },
+                {new LogicalKeySet(key1: LogicalKeyboardKey.arrowUp), new DirectionalFocusIntent()},
+
+                // Scrolling
+                {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.control, key2: LogicalKeyboardKey.arrowUp),
+                    new ScrollIntent(direction: AxisDirection.up)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.control, key2: LogicalKeyboardKey.arrowDown),
+                    new ScrollIntent(direction: AxisDirection.down)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.control, key2: LogicalKeyboardKey.arrowLeft),
+                    new ScrollIntent(direction: AxisDirection.left)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.control, key2: LogicalKeyboardKey.arrowRight),
+                    new ScrollIntent(direction: AxisDirection.right)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.pageUp),
+                    new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.pageDown),
+                    new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)
+                }
+            };
+
+        // Default shortcuts for the web platform.
+        public static readonly Dictionary<LogicalKeySet, Intent> _defaultWebShortcuts =
+            new Dictionary<LogicalKeySet, Intent> {
+                // Activation
+                {new LogicalKeySet(key1: LogicalKeyboardKey.space), new Intent(key: ActivateAction.key)},
+
+                // Keyboard traversal.
+                {new LogicalKeySet(key1: LogicalKeyboardKey.tab), new Intent(key: NextFocusAction.key)}, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.shift, key2: LogicalKeyboardKey.tab),
+                    new Intent(key: PreviousFocusAction.key)
+                },
+
+                // Scrolling
+                {new LogicalKeySet(key1: LogicalKeyboardKey.arrowUp), new ScrollIntent(direction: AxisDirection.up)}, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowDown),
+                    new ScrollIntent(direction: AxisDirection.down)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowLeft),
+                    new ScrollIntent(direction: AxisDirection.left)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowRight),
+                    new ScrollIntent(direction: AxisDirection.right)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.pageUp),
+                    new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.pageDown),
+                    new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)
+                }
+            };
+
+        // Default shortcuts for the macOS platform.
+        public static readonly Dictionary<LogicalKeySet, Intent> _defaultMacOsShortcuts =
+            new Dictionary<LogicalKeySet, Intent> {
+                // Activation
+                {new LogicalKeySet(key1: LogicalKeyboardKey.enter), new Intent(key: ActivateAction.key)},
+                {new LogicalKeySet(key1: LogicalKeyboardKey.space), new Intent(key: ActivateAction.key)},
+
+                // Keyboard traversal
+                {new LogicalKeySet(key1: LogicalKeyboardKey.tab), new Intent(key: NextFocusAction.key)}, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.shift, key2: LogicalKeyboardKey.tab),
+                    new Intent(key: PreviousFocusAction.key)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowLeft),
+                    new DirectionalFocusIntent(direction: TraversalDirection.left)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowRight),
+                    new DirectionalFocusIntent(direction: TraversalDirection.right)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.arrowDown),
+                    new DirectionalFocusIntent(direction: TraversalDirection.down)
+                },
+                {new LogicalKeySet(key1: LogicalKeyboardKey.arrowUp), new DirectionalFocusIntent()},
+
+                // Scrolling
+                {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.meta, key2: LogicalKeyboardKey.arrowUp),
+                    new ScrollIntent(direction: AxisDirection.up)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.meta, key2: LogicalKeyboardKey.arrowDown),
+                    new ScrollIntent(direction: AxisDirection.down)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.meta, key2: LogicalKeyboardKey.arrowLeft),
+                    new ScrollIntent(direction: AxisDirection.left)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.meta, key2: LogicalKeyboardKey.arrowRight),
+                    new ScrollIntent(direction: AxisDirection.right)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.pageUp),
+                    new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)
+                }, {
+                    new LogicalKeySet(key1: LogicalKeyboardKey.pageDown),
+                    new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)
+                }
+            };
+
+        /// The default value of [WidgetsApp.actions].
+        public static readonly Dictionary<LocalKey, ActionFactory> defaultActions =
+            new Dictionary<LocalKey, ActionFactory> {
+                {DoNothingAction.key, () => new DoNothingAction()},
+                {RequestFocusAction.key, () => new RequestFocusAction()},
+                {NextFocusAction.key, () => new NextFocusAction()},
+                {PreviousFocusAction.key, () => new PreviousFocusAction()},
+                {DirectionalFocusAction.key, () => new DirectionalFocusAction()},
+                {ScrollAction.key, () => new ScrollAction()}
+            };
+
+        public readonly Dictionary<LocalKey, ActionFactory> actions;
+        public readonly bool checkerboardOffscreenLayers;
+        public readonly bool checkerboardRasterCacheImages;
+        public readonly Color color;
+        public readonly bool debugShowCheckedModeBanner;
+        public readonly bool debugShowWidgetInspector;
+        public readonly InspectorSelectButtonBuilder inspectorSelectButtonBuilder;
+        public readonly Locale locale;
+        public readonly LocaleListResolutionCallback localeListResolutionCallback;
+        public readonly LocaleResolutionCallback localeResolutionCallback;
+        public readonly List<LocalizationsDelegate> localizationsDelegates;
+        public readonly InitialRouteListFactory onGenerateInitialRoutes;
-        public readonly InitialRouteListFactory onGenerateInitialRoutes;
+        public readonly GenerateAppTitle onGenerateTitle;
-        public readonly TextStyle textStyle;
-        public readonly Window window;
+        public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
-        public readonly Locale locale;
-        public readonly List<LocalizationsDelegate> localizationsDelegates;
-        public readonly LocaleListResolutionCallback localeListResolutionCallback;
-        public readonly LocaleResolutionCallback localeResolutionCallback;
+        public readonly bool showSemanticsDebugger;
+        public readonly TextStyle textStyle;
-        public readonly GenerateAppTitle onGenerateTitle;
-        public readonly Color color;
-        public readonly InspectorSelectButtonBuilder inspectorSelectButtonBuilder;
-        
-        public static bool showPerformanceOverlayOverride = false;
-        public static bool debugShowWidgetInspectorOverride = false;
-        public static bool debugAllowBannerOverride = true;
-        public readonly bool debugShowCheckedModeBanner;
-        public readonly bool checkerboardRasterCacheImages;
-        public readonly bool checkerboardOffscreenLayers;
-        public readonly bool showSemanticsDebugger;
-        public readonly bool debugShowWidgetInspector;
-        public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
-        public readonly  Dictionary<LocalKey, ActionFactory> actions;
-        
+        public readonly Window window;
+
         public WidgetsApp(
             Key key = null,
             GlobalKey<NavigatorState> navigatorKey = null,
             InspectorSelectButtonBuilder inspectorSelectButtonBuilder = null,
             Dictionary<LogicalKeySet, Intent> shortcuts = null,
             Dictionary<LocalKey, ActionFactory> actions = null
-        ) : base(key) {
-            
+        ) : base(key: key) {
             routes = routes ?? new Dictionary<string, WidgetBuilder>();
             supportedLocales = supportedLocales ?? new List<Locale> {new Locale("en", "US")};
             window = Window.instance;
             this.inspectorSelectButtonBuilder = inspectorSelectButtonBuilder;
             this.shortcuts = shortcuts;
             this.actions = actions;
-            
+
-                );
+            );
-                !this.routes.ContainsKey(Navigator.defaultRouteName),
+                !this.routes.ContainsKey(key: Navigator.defaultRouteName),
                 () => "If the home property is specified, the routes table " +
                       "cannot include an entry for \" / \", since it would be redundant."
             );
                 home != null ||
-                this.routes.ContainsKey(Navigator.defaultRouteName) ||
+                this.routes.ContainsKey(key: Navigator.defaultRouteName) ||
                 onGenerateRoute != null ||
                 onUnknownRoute != null,
                 () => "Either the home property must be specified, " +
                       "app is started with an intent that specifies an unknown route."
             );
             D.assert(
-                (home != null ||
-                 routes.isNotEmpty() ||
-                 onGenerateRoute != null ||
-                 onUnknownRoute != null)
+                home != null ||
+                routes.isNotEmpty() ||
+                onGenerateRoute != null ||
+                onUnknownRoute != null
-                (builder != null &&
-                 navigatorKey == null &&
-                 initialRoute == null &&
-                 navigatorObservers.isEmpty()),()=>
-                "If no route is provided using " +
-                "home, routes, onGenerateRoute, or onUnknownRoute, " +
-                "a non-null callback for the builder property must be provided, " +
-                "and the other navigator-related properties, " +
-                "navigatorKey, initialRoute, and navigatorObservers, " +
-                "must have their initial values " +
-                "(null, null, and the empty list, respectively).");
+                builder != null &&
+                navigatorKey == null &&
+                initialRoute == null &&
+                navigatorObservers.isEmpty(), () =>
+                    "If no route is provided using " +
+                    "home, routes, onGenerateRoute, or onUnknownRoute, " +
+                    "a non-null callback for the builder property must be provided, " +
+                    "and the other navigator-related properties, " +
+                    "navigatorKey, initialRoute, and navigatorObservers, " +
+                    "must have their initial values " +
+                    "(null, null, and the empty list, respectively).");
 
             D.assert(
                 builder != null ||
                       "pageRouteBuilder must be specified so that the default handler " +
                       "will know what kind of PageRoute transition to build."
             );
-        } 
-        
-        public static readonly Dictionary<LogicalKeySet, Intent> _defaultShortcuts = new Dictionary<LogicalKeySet, Intent>(){
-            // Activation
-            {new LogicalKeySet(LogicalKeyboardKey.enter), new Intent(ActivateAction.key)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.space), new Intent(ActivateAction.key)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.gameButtonA), new Intent(ActivateAction.key)},
+        }
-            // Keyboard traversal.
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.tab), new Intent(NextFocusAction.key)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab), new Intent(PreviousFocusAction.key)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowLeft), new DirectionalFocusIntent(TraversalDirection.left)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowRight), new DirectionalFocusIntent(TraversalDirection.right)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowDown), new DirectionalFocusIntent(TraversalDirection.down)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowUp), new DirectionalFocusIntent(TraversalDirection.up)},
-            // Scrolling
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.arrowUp), new ScrollIntent(direction: AxisDirection.up)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.arrowDown), new ScrollIntent(direction: AxisDirection.down)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.arrowLeft), new ScrollIntent(direction: AxisDirection.left)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.arrowRight), new ScrollIntent(direction: AxisDirection.right)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.pageUp), new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.pageDown), new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)},
-        };
-
-        // Default shortcuts for the web platform.
-        public static readonly Dictionary<LogicalKeySet, Intent> _defaultWebShortcuts = new Dictionary<LogicalKeySet, Intent>(){
-            // Activation
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.space), new Intent(ActivateAction.key)},
-
-            // Keyboard traversal.
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.tab), new Intent(NextFocusAction.key)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab),new Intent(PreviousFocusAction.key)},
-
-            // Scrolling
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowUp), new ScrollIntent(direction: AxisDirection.up)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowDown), new ScrollIntent(direction: AxisDirection.down)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowLeft), new ScrollIntent(direction: AxisDirection.left)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowRight), new ScrollIntent(direction: AxisDirection.right)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.pageUp), new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)},
-            {new widgets.LogicalKeySet(LogicalKeyboardKey.pageDown), new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)},
-        };
-
-        // Default shortcuts for the macOS platform.
-        public static readonly Dictionary<LogicalKeySet, Intent> _defaultMacOsShortcuts = new Dictionary<LogicalKeySet, Intent>(){
-            // Activation
-            {new LogicalKeySet(LogicalKeyboardKey.enter), new Intent(ActivateAction.key)},
-            {new LogicalKeySet(LogicalKeyboardKey.space), new Intent(ActivateAction.key)},
-
-            // Keyboard traversal
-            {new LogicalKeySet(LogicalKeyboardKey.tab), new Intent(NextFocusAction.key)},
-            {new LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab), new Intent(PreviousFocusAction.key)},
-            {new LogicalKeySet(LogicalKeyboardKey.arrowLeft), new DirectionalFocusIntent(TraversalDirection.left)},
-            {new LogicalKeySet(LogicalKeyboardKey.arrowRight), new DirectionalFocusIntent(TraversalDirection.right)},
-            {new LogicalKeySet(LogicalKeyboardKey.arrowDown), new DirectionalFocusIntent(TraversalDirection.down)},
-            {new LogicalKeySet(LogicalKeyboardKey.arrowUp), new DirectionalFocusIntent(TraversalDirection.up)},
-
-            // Scrolling
-            {new LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.arrowUp), new  ScrollIntent(direction: AxisDirection.up)},
-            {new LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.arrowDown), new ScrollIntent(direction: AxisDirection.down)},
-            {new LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.arrowLeft), new ScrollIntent(direction: AxisDirection.left)},
-            {new LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.arrowRight), new ScrollIntent(direction: AxisDirection.right)},
-            {new LogicalKeySet(LogicalKeyboardKey.pageUp), new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)},
-            {new LogicalKeySet(LogicalKeyboardKey.pageDown), new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)},
-        };
-
-  
+
                 switch (Application.platform) {
                     case RuntimePlatform.Android:
                     //case TargetPlatform.fuchsia:
                         // No keyboard support on iOS yet.
                         break;
                 }
+
-    /// The default value of [WidgetsApp.actions].
-    public static readonly Dictionary<LocalKey, ActionFactory> defaultActions = new Dictionary<LocalKey, ActionFactory>(){
-        {DoNothingAction.key, () => new  DoNothingAction()},
-        {RequestFocusAction.key, () => new RequestFocusAction()},
-        {NextFocusAction.key, () => new NextFocusAction()},
-        {PreviousFocusAction.key, () => new PreviousFocusAction()},
-        {DirectionalFocusAction.key, () => new DirectionalFocusAction()},
-        {ScrollAction.key, () => new ScrollAction()},
-    };
-        
-    
+
+        Locale _locale;
+
+        GlobalKey<NavigatorState> _navigator;
+
+        List<LocalizationsDelegate> _localizationsDelegates {
+            get {
+                var _delegates = new List<LocalizationsDelegate>();
+                if (widget.localizationsDelegates != null) {
+                    _delegates.AddRange(collection: widget.localizationsDelegates);
+                }
+
+                _delegates.Add(item: DefaultWidgetsLocalizations.del);
+                return _delegates;
+            }
+        }
+
         public void didChangeMetrics() {
             setState();
         }
         }
 
         public void didChangeLocales(List<Locale> locale) {
-            Locale newLocale = _resolveLocales(locale, widget.supportedLocales);
+            var newLocale = _resolveLocales(preferredLocales: locale, supportedLocales: widget.supportedLocales);
-        List<LocalizationsDelegate> _localizationsDelegates {
-            get {
-                List<LocalizationsDelegate> _delegates = new List<LocalizationsDelegate>();
-                if (widget.localizationsDelegates != null) {
-                    _delegates.AddRange(widget.localizationsDelegates);
-                }
+        public Future<bool> didPopRoute() {
+            ///async
+            D.assert(result: mounted);
+            var navigator = _navigator?.currentState;
+            if (navigator == null) {
+                return Future.value(false).to<bool>();
+            }
+
+            return navigator.maybePop<bool>();
+        }
-                _delegates.Add(DefaultWidgetsLocalizations.del);
-                return _delegates;
+        public Future<bool> didPushRoute(string route) {
+            D.assert(result: mounted);
+            var navigator = _navigator?.currentState;
+            if (navigator == null) {
+                return Future.value(false).to<bool>();
+
+            navigator.pushNamed<bool>(routeName: route);
+            return Future.value(true).to<bool>();
+        }
+
+        public void didChangeAccessibilityFeatures() {
         }
 
         public override void initState() {
-                _resolveLocales(new List<Locale> {new Locale("en", "US")}, widget.supportedLocales);
+                _resolveLocales(new List<Locale> {new Locale("en", "US")}, supportedLocales: widget.supportedLocales);
-            base.didUpdateWidget(oldWidget);
+            base.didUpdateWidget(oldWidget: oldWidget);
             if (widget.navigatorKey != ((WidgetsApp) oldWidget).navigatorKey) {
                 _updateNavigator();
             }
             base.dispose();
         }
 
-        GlobalKey<NavigatorState> _navigator;
-
         void _updateNavigator() {
             _navigator = widget.navigatorKey ?? new GlobalObjectKey<NavigatorState>(this);
         }
             var pageContentBuilder = name == Navigator.defaultRouteName && widget.home != null
                 ? context => widget.home
-                : widget.routes.getOrDefault(name);
+                : widget.routes.getOrDefault(key: name);
 
             if (pageContentBuilder != null) {
                 D.assert(widget.pageRouteBuilder != null,
-                    settings,
-                    pageContentBuilder
+                    settings: settings,
+                    builder: pageContentBuilder
                 );
                 D.assert(route != null,
                     () => "The pageRouteBuilder for WidgetsApp must return a valid non-null Route.");
             if (widget.onGenerateRoute != null) {
-                return widget.onGenerateRoute(settings);
+                return widget.onGenerateRoute(settings: settings);
-        public Future<bool> didPopRoute() {
-            ///async
-            D.assert(mounted);
-            var navigator = _navigator?.currentState;
-            if (navigator == null) {
-                return Future.value(false).to<bool>();
-            }
-
-            return navigator.maybePop<bool>();
-        }
-
-        public Future<bool> didPushRoute(string route) {
-            D.assert(mounted);
-            var navigator = _navigator?.currentState;
-            if (navigator == null) {
-                return Future.value(false).to<bool>();
-            }
-
-            navigator.pushNamed<bool>(route);
-            return Future.value(true).to<bool>();
-        }
-
-        public void didChangeAccessibilityFeatures() {}
-
-                        $"Generators for routes are searched for in the following order:\n" +
+                        "Generators for routes are searched for in the following order:\n" +
                         " 1. For the \"/\" route, the \"home\" property, if non-null, is used.\n" +
                         " 2. Otherwise, the \"routes\" table is used, if it has an entry for " +
                         "the route.\n" +
 
                 return true;
             });
-            var result = widget.onUnknownRoute(settings) as Route<object>;
+            var result = widget.onUnknownRoute(settings: settings) as Route<object>;
             D.assert(() => {
                 if (result == null) {
                     throw new UIWidgetsError(
             return result;
         }
 
-        Locale _locale;
-
-                Locale locale =
-                    widget.localeListResolutionCallback(preferredLocales, widget.supportedLocales);
+                var locale =
+                    widget.localeListResolutionCallback(locales: preferredLocales,
+                        supportedLocales: widget.supportedLocales);
                 if (locale != null) {
                     return locale;
                 }
-                Locale locale = widget.localeResolutionCallback(
+                var locale = widget.localeResolutionCallback(
-                    widget.supportedLocales
+                    supportedLocales: widget.supportedLocales
                 );
                 if (locale != null) {
                     return locale;
-            return basicLocaleListResolution(preferredLocales, supportedLocales);
+            return basicLocaleListResolution(preferredLocales: preferredLocales, supportedLocales: supportedLocales);
         }
 
 
             }
 
-            Dictionary<string, Locale> allSupportedLocales = new Dictionary<string, Locale>();
-            Dictionary<string, Locale> languageAndCountryLocales = new Dictionary<string, Locale>();
-            Dictionary<string, Locale> languageAndScriptLocales = new Dictionary<string, Locale>();
-            Dictionary<string, Locale> languageLocales = new Dictionary<string, Locale>();
-            Dictionary<string, Locale> countryLocales = new Dictionary<string, Locale>();
-            foreach (Locale locale in supportedLocales) {
+            var allSupportedLocales = new Dictionary<string, Locale>();
+            var languageAndCountryLocales = new Dictionary<string, Locale>();
+            var languageAndScriptLocales = new Dictionary<string, Locale>();
+            var languageLocales = new Dictionary<string, Locale>();
+            var countryLocales = new Dictionary<string, Locale>();
+            foreach (var locale in supportedLocales) {
-                languageLocales.putIfAbsent(locale.languageCode, () => locale);
-                countryLocales.putIfAbsent(locale.countryCode, () => locale);
+                languageLocales.putIfAbsent(key: locale.languageCode, () => locale);
+                countryLocales.putIfAbsent(key: locale.countryCode, () => locale);
-
-            for (int localeIndex = 0; localeIndex < preferredLocales.Count; localeIndex++) {
-                Locale userLocale = preferredLocales[localeIndex];
+            for (var localeIndex = 0; localeIndex < preferredLocales.Count; localeIndex++) {
+                var userLocale = preferredLocales[index: localeIndex];
                 if (allSupportedLocales.ContainsKey(userLocale.languageCode + "_" + userLocale.scriptCode + "_" +
                                                     userLocale.countryCode)) {
                     return userLocale;
                     Locale match = null;
                     if (languageAndScriptLocales.TryGetValue(userLocale.languageCode + "_" + userLocale.scriptCode,
-                        out match)) {
+                        value: out match)) {
                         if (match != null) {
                             return match;
                         }
                     //Locale match = languageAndCountryLocales['${userLocale.languageCode}_${userLocale.countryCode}'];
                     Locale match = null;
                     if (languageAndCountryLocales.TryGetValue(userLocale.languageCode + "_" + userLocale.countryCode,
-                        out match)) {
+                        value: out match)) {
                         if (match != null) {
                             return match;
                         }
                     return matchesLanguageCode;
                 }
 
-                if (languageLocales.ContainsKey(userLocale.languageCode)) {
-                    matchesLanguageCode = languageLocales[userLocale.languageCode];
+                if (languageLocales.ContainsKey(key: userLocale.languageCode)) {
+                    matchesLanguageCode = languageLocales[key: userLocale.languageCode];
 
                     if (localeIndex == 0 &&
                         !(localeIndex + 1 < preferredLocales.Count && preferredLocales[localeIndex + 1].languageCode ==
 
 
                 if (matchesCountryCode == null && userLocale.countryCode != null) {
-                    if (countryLocales.ContainsKey(userLocale.countryCode)) {
-                        matchesCountryCode = countryLocales[userLocale.countryCode];
+                    if (countryLocales.ContainsKey(key: userLocale.countryCode)) {
+                        matchesCountryCode = countryLocales[key: userLocale.countryCode];
-            Locale resolvedLocale = matchesLanguageCode ?? matchesCountryCode ?? supportedLocales.first();
+            var resolvedLocale = matchesLanguageCode ?? matchesCountryCode ?? supportedLocales.first();
             return resolvedLocale;
         }
 
         }
-        
+
-                HashSet<Type> unsupportedTypes = new HashSet<Type>();
+                var unsupportedTypes = new HashSet<Type>();
-                    unsupportedTypes.Add(_delegate.type);
+                    unsupportedTypes.Add(item: _delegate.type);
-                foreach ( LocalizationsDelegate _delegate in _localizationsDelegates) {
-                    if (!unsupportedTypes.Contains(_delegate.type))
+
+                foreach (var _delegate in _localizationsDelegates) {
+                    if (!unsupportedTypes.Contains(item: _delegate.type)) {
-                    if (_delegate.isSupported(appLocale))
-                        unsupportedTypes.Remove(_delegate.type);
+                    }
+
+                    if (_delegate.isSupported(locale: appLocale)) {
+                        unsupportedTypes.Remove(item: _delegate.type);
+                    }
-                if (unsupportedTypes.isEmpty())
+
+                if (unsupportedTypes.isEmpty()) {
-                List<string> list = new List<string> {"CupertinoLocalizations"};
-                List<string> unsupportedTypesList = new List<string>();
+                }
+
+                var list = new List<string> {"CupertinoLocalizations"};
+                var unsupportedTypesList = new List<string>();
-                if (unsupportedTypesList.SequenceEqual(list))
+
+                if (unsupportedTypesList.SequenceEqual(second: list)) {
+                }
-                StringBuilder message = new StringBuilder();
+                var message = new StringBuilder();
-                "localization delegates."
-                    );
-                foreach ( Type unsupportedType in unsupportedTypes) {
-                   
-                    if (unsupportedType.ToString() == "CupertinoLocalizations")
+                    "localization delegates."
+                );
+                foreach (var unsupportedType in unsupportedTypes) {
+                    if (unsupportedType.ToString() == "CupertinoLocalizations") {
+                    }
+
-                        "> A "+ unsupportedType + " delegate that supports the " + appLocale + "locale was not found."
+                        "> A " + unsupportedType + " delegate that supports the " + appLocale + "locale was not found."
+
-                "information about configuring an app's locale, supportedLocales,\n" +
-                "and localizationsDelegates parameters."
-                    );
+                    "information about configuring an app's locale, supportedLocales,\n" +
+                    "and localizationsDelegates parameters."
+                );
-            
+
                 return true;
             });
             return true;
             Widget navigator = null;
             if (_navigator != null) {
-                RouteListFactory routeListFactory = (state, route) => {return widget.onGenerateInitialRoutes(route); };
+                RouteListFactory routeListFactory = (state, route) => {
+                    return widget.onGenerateInitialRoutes(initialRoute: route);
+                };
-                    initialRoute: 
-                    WidgetsBinding.instance.window.defaultRouteName != Navigator.defaultRouteName
+                    initialRoute: WidgetsBinding.instance.window.defaultRouteName != Navigator.defaultRouteName
                         ? WidgetsBinding.instance.window.defaultRouteName
                         : widget.initialRoute ?? WidgetsBinding.instance.window.defaultRouteName,
                     onGenerateRoute: _onGenerateRoute,
                 );
             }
 
-
-                    builder: _context => { return widget.builder(_context, navigator); }
-                );
+                    builder: context1 => { return widget.builder(context: context1, child: navigator); });
             }
             else {
                 D.assert(navigator != null);
             }
 
             PerformanceOverlay performanceOverlay = null;
-           
+
-            } else if (widget.checkerboardRasterCacheImages || widget.checkerboardOffscreenLayers) {
+            }
+            else if (widget.checkerboardRasterCacheImages || widget.checkerboardOffscreenLayers) {
                 performanceOverlay = new PerformanceOverlay(
                     checkerboardRasterCacheImages: widget.checkerboardRasterCacheImages,
                     checkerboardOffscreenLayers: widget.checkerboardOffscreenLayers
+
-                        new Positioned(top: 0.0f,
-                            left: 0.0f,
-                            right: 0.0f,
-                            child: performanceOverlay)
-                    });
+                        new Positioned(top: 0.0f, left: 0.0f, right: 0.0f, child: performanceOverlay)
+                    }
+                );
+
             D.assert(() => {
                 if (widget.debugShowWidgetInspector || WidgetsApp.debugShowWidgetInspectorOverride) {
                     result = new WidgetInspector(
                 }
+
+
+            
+            //Fix Me !!
+            //TODO: the following line is a work-around for some potential TextDirection bug
+            //In the home page of the Shrine sample, the positions of the buttons are not correct, which is 
+            //determined by the TextDirection of some widget. we should fix it!
+            result = new Directionality(child: result, TextDirection.ltr);
-                    builder: (BuildContext context1)=> {
-                    string title1 = widget.onGenerateTitle(context1);
-                    D.assert(title1 != null,()=> "onGenerateTitle must return a non-null String");
-                    return new Title(
-                        title: title1,
-                        color: widget.color,
-                        child: result
-                    );
-                }
+                    builder: context2 => {
+                        var _title = widget.onGenerateTitle(context: context2);
+                        D.assert(_title != null, () => "onGenerateTitle must return a non-null String");
+                        return new Title(
+                            title: _title,
+                            color: widget.color,
+                            child: result
+                        );
+                    }
-            } else {
+            }
+            else {
                 title = new Title(
                     title: widget.title,
                     color: widget.color,
 
-            Locale appLocale = widget.locale != null
-                ? _resolveLocales(new List<Locale> {widget.locale}, widget.supportedLocales)
+            var appLocale = widget.locale != null
+                ? _resolveLocales(new List<Locale> {widget.locale}, supportedLocales: widget.supportedLocales)
-            D.assert(_debugCheckLocalizations(appLocale));
-            
-            result = new Shortcuts(
+
+            D.assert(_debugCheckLocalizations(appLocale: appLocale));
+
+            return new Shortcuts(
                 shortcuts: widget.shortcuts ?? WidgetsApp.defaultShortcuts,
                 debugLabel: "<Default WidgetsApp Shortcuts>",
                 child: new Actions(
                     )
                 )
             );
-
-            return result;
-            return new _InspectorSelectButton(onPressed);
+            return new _InspectorSelectButton(onPressed: onPressed);
+        public readonly Widget child;
+
-        public readonly Widget child;
-    
-    class _MediaQueryFromWindowsState : State<_MediaQueryFromWindow>,WidgetsBindingObserver {
-        public override void initState() {
-            base.initState();
-            WidgetsBinding.instance.addObserver(this);
+    class _MediaQueryFromWindowsState : State<_MediaQueryFromWindow>, WidgetsBindingObserver {
+        public void didChangeAccessibilityFeatures() {
+            setState(() => { });
-        public  void didChangeAccessibilityFeatures() {
-            setState(()=> {
-            });
+
+        public void didChangeMetrics() {
+            setState(() => { });
-        public  void didChangeMetrics() {
-            setState(()=>{
-              
-            });
+
+        public void didChangeTextScaleFactor() {
+            setState(() => { });
-        public  void didChangeTextScaleFactor() {
-            setState(()=> {
-            });
-        }
+
-            setState(()=> {
-            });
+            setState(() => { });
         }
 
         public void didChangeLocales(List<Locale> locale) {
             throw new NotImplementedException();
         }
 
+        public override void initState() {
+            base.initState();
+            WidgetsBinding.instance.addObserver(this);
+        }
+
-                data: MediaQueryData.fromWindow(WidgetsBinding.instance.window),
+                data: MediaQueryData.fromWindow(window: WidgetsBinding.instance.window),
+
-    
+
     class _InspectorSelectButton : StatelessWidget {
         public readonly GestureTapCallback onPressed;
 
-        ) : base(key) {
+        ) : base(key: key) {
             this.onPressed = () => onPressed();
         }
 

com.unity.uiwidgets/Runtime/widgets/basic.cs

             );
         }
 
-        void updateRenderObject(BuildContext context, RenderMouseRegion renderObject) {
+        public override void updateRenderObject(BuildContext context, RenderObject renderObject) {
+            RenderMouseRegion _renderObject = (RenderMouseRegion) renderObject;
-            renderObject.onEnter = widget.onEnter;
-            renderObject.onHover = widget.onHover;
-            renderObject.onExit = owner.getHandleExit();
-            renderObject.opaque = widget.opaque;
+            _renderObject.onEnter = widget.onEnter;
+            _renderObject.onHover = widget.onHover;
+            _renderObject.onExit = owner.getHandleExit();
+            _renderObject.opaque = widget.opaque;
         }
     }
 

com.unity.uiwidgets/Runtime/widgets/focus_manager.cs

 using System.Linq;
 using Unity.UIWidgets.async2;
 using Unity.UIWidgets.cupertino;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.painting;
         
         public override List<DiagnosticsNode> debugDescribeChildren() {
             int count = 1;
-            return _children.Select((FocusNode child)=> {
-              return child.toDiagnosticsNode(name: $"Child {count++}");
-            }).ToList();
+            return LinqUtils<DiagnosticsNode, FocusNode>.SelectList(_children, (FocusNode child) => { 
+                return child.toDiagnosticsNode(name: $"Child {count++}");
+            });
         }
         
         public override string toStringShort() {//override
             } 
             List<string> childList = new List<string>();
             _focusedChildren.Reverse();
-            childList = _focusedChildren.Select((FocusNode child)=> {
-              return child.toStringShort();
-            }).ToList();
+            childList = LinqUtils<string,FocusNode>.SelectList(_focusedChildren, (FocusNode child) => { 
+                return child.toStringShort();
+            });
             properties.add(new EnumerableProperty<string>("focusedChildren", childList, defaultValue: new List<string>()));
         }
     }
                     _dirtyNodes.Add(_primaryFocus);
                 }
             }
-            D.assert(FocusManagerUtils._focusDebug($"Notifying {_dirtyNodes.Count} dirty nodes:", 
-                _dirtyNodes.ToList().Select((FocusNode node) => {
+            D.assert(FocusManagerUtils._focusDebug($"Notifying {_dirtyNodes.Count} dirty nodes:",
+                LinqUtils<string,FocusNode>.SelectList(_dirtyNodes, ((FocusNode node) => {
-                }).ToList()));
+                }))
+            ));
             foreach ( FocusNode node in _dirtyNodes) {
                 node._notify();
             }

com.unity.uiwidgets/Runtime/widgets/focus_traversal.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
 using Unity.UIWidgets.widgets;
         public static TextDirection _findDirectionality(BuildContext context) {
             return (context.getElementForInheritedWidgetOfExactType<Directionality>().widget as Directionality).textDirection;
         }
-        public static TextDirection commonDirectionalityOf(List<_ReadingOrderSortData> list) { 
-            IEnumerable<HashSet<Directionality>> allAncestors = list.Select((_ReadingOrderSortData member) => new HashSet<Directionality>(member.directionalAncestors)); 
+        public static TextDirection commonDirectionalityOf(List<_ReadingOrderSortData> list) {
+            IEnumerable<HashSet<Directionality>> allAncestors = LinqUtils<HashSet<Directionality>, _ReadingOrderSortData>.SelectList(list, ((_ReadingOrderSortData member) => new HashSet<Directionality>(member.directionalAncestors)));
             HashSet<Directionality> common = null; 
             foreach ( HashSet<Directionality> ancestorSet in allAncestors) { 
                 common = common ?? ancestorSet; 
         Rect _rect; 
         Rect  rect {
             get {if (_rect == null) {
-                    foreach(Rect rect in members.Select(
+                    foreach(Rect rect in LinqUtils<Rect,_ReadingOrderSortData>.SelectList(members,
                         (_ReadingOrderSortData data) => data.rect)){
                         _rect = _rect ?? rect;
                         _rect = _rect.expandToInclude(rect);
 
             List<_ReadingOrderSortData> inBand(_ReadingOrderSortData current, IEnumerable<_ReadingOrderSortData> _candidates) { 
                 Rect band = Rect.fromLTRB(float.NegativeInfinity, current.rect.top, float.PositiveInfinity, current.rect.bottom);
-                return _candidates.Where((_ReadingOrderSortData item)=> {
+                return LinqUtils<_ReadingOrderSortData>.WhereList(_candidates,((_ReadingOrderSortData item)=> {
-                }).ToList();
+                }));
             }
             List<_ReadingOrderSortData> inBandOfTop = inBand(topmost, candidates);
             D.assert(topmost.rect.isEmpty || inBandOfTop.isNotEmpty());
               ); 
                 return a.order.CompareTo(b.order); 
             }); 
-            return ordered.Select((_OrderedFocusInfo info) => info.node).Concat(unordered);
+           return LinqUtils<FocusNode,_OrderedFocusInfo>.SelectList(ordered,((_OrderedFocusInfo info) => info.node)).Concat(unordered);
         }
     }
 

com.unity.uiwidgets/Runtime/widgets/framework.cs

 using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.CompilerServices;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.rendering;
 using Unity.UIWidgets.ui;
 
                             if (keys.isNotEmpty()) {
                                 var keyStringCount = new Dictionary<string, int>();
-                                foreach (string key in keys.Select(key => key.ToString())) {
+                                foreach (string key in LinqUtils<string, GlobalKey>.SelectList(keys,(key => key.ToString()))) {
                                     if (keyStringCount.ContainsKey(key)) {
                                         keyStringCount[key] += 1;
                                     }
 
                                 var elements = _debugElementsThatWillNeedToBeRebuiltDueToGlobalKeyShenanigans.Keys;
                                 var elementStringCount = new Dictionary<string, int>();
-                                foreach (string element in elements.Select(element => element.ToString())) {
+                                foreach (string element in LinqUtils<string, Element>.SelectList(elements,(element => element.ToString()))) {
                                     if (elementStringCount.ContainsKey(element)) {
                                         elementStringCount[element] += 1;
                                     }
         public static DiagnosticsNode describeElements(string name, IEnumerable<Element> elements) {
             return new DiagnosticsBlock(
                 name: name,
-                children: elements.Select((Element element) => new DiagnosticsProperty<Element>("", element))
-                    .ToList<DiagnosticsNode>(),
+                children: LinqUtils<DiagnosticsNode, Element>.SelectList(elements,((Element element) => new DiagnosticsProperty<Element>("", element))),
                 allowTruncate: true
             );
         }
 
             properties.add(new FlagProperty("dirty", value: dirty, ifTrue: "dirty"));
             if (_dependencies != null && _dependencies.isNotEmpty()) {
-                List<DiagnosticsNode> diagnosticsDependencies = _dependencies
-                    .Select((InheritedElement element) =>
-                        element.widget.toDiagnosticsNode(style: DiagnosticsTreeStyle.sparse))
-                    .ToList();
+                List<DiagnosticsNode> diagnosticsDependencies = LinqUtils<DiagnosticsNode, InheritedElement>
+                    .SelectList(_dependencies, ((InheritedElement element) =>
+                        element.widget.toDiagnosticsNode(style: DiagnosticsTreeStyle.sparse)));
                 properties.add(new DiagnosticsProperty<List<DiagnosticsNode>>("dependencies", diagnosticsDependencies));
             }
         }
         }
 
         protected IEnumerable<Element> children {
-            get { return _children.Where((child) => !_forgottenChildren.Contains(child)); }
+            get { return LinqUtils<Element>.WhereList(_children,((child) => !_forgottenChildren.Contains(child))); }
         }
 
         List<Element> _children;

com.unity.uiwidgets/Runtime/widgets/gesture_detector.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.rendering;
                 properties.add(DiagnosticsNode.message("DISPOSED"));
             }
             else {
-                List<string> gestures = _recognizers.Values.Select(recognizer => recognizer.debugDescription)
-                    .ToList();
+                List<string> gestures = LinqUtils<string, GestureRecognizer>.SelectList(_recognizers.Values,  (recognizer => recognizer.debugDescription));
                 properties.add(new EnumerableProperty<string>("gestures", gestures, ifEmpty: "<none>"));
                 properties.add(new EnumerableProperty<GestureRecognizer>("recognizers", _recognizers.Values,
                     level: DiagnosticLevel.fine));

com.unity.uiwidgets/Runtime/widgets/heroes.cs

 using System.Collections.Generic;
 using System.Linq;
 using Unity.UIWidgets.animation;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.painting;
 using Unity.UIWidgets.rendering;
                        && flight._proxyAnimation.isDismissed;
             }
 
-             List<_HeroFlight> invalidFlights = _flights.Values
-                .Where(isInvalidFlight)
-                .ToList();
+            List<_HeroFlight> invalidFlights = LinqUtils<_HeroFlight>.WhereList(_flights.Values, isInvalidFlight);
              foreach ( _HeroFlight flight in invalidFlights) {
                 flight._handleAnimationUpdate(AnimationStatus.dismissed);
             }

com.unity.uiwidgets/Runtime/widgets/image.cs

 using Unity.UIWidgets.ui;
 using UnityEngine;
 using Color = Unity.UIWidgets.ui.Color;
-using Object = System.Object;
 using Rect = Unity.UIWidgets.ui.Rect;
 
 namespace Unity.UIWidgets.widgets {
-                bundle: DefaultAssetBundle.of(context),
-                devicePixelRatio: MediaQuery.of(context, nullOk: true)?.devicePixelRatio ?? 1.0f,
-                locale: Localizations.localeOf(context, nullOk: true),
+                DefaultAssetBundle.of(context: context),
+                MediaQuery.of(context: context, true)?.devicePixelRatio ?? 1.0f,
+                Localizations.localeOf(context: context, true),
                 size: size,
                 platform: Application.platform
             );
             Size size = null,
             ImageErrorListener onError = null
         ) {
-            ImageConfiguration config = createLocalImageConfiguration(context, size: size);
-            Completer completer = Completer.create();
-            ImageStream stream = provider.resolve(config);
+            var config = createLocalImageConfiguration(context: context, size: size);
+            var completer = Completer.create();
+            var stream = provider.resolve(configuration: config);
-                (ImageInfo image, bool sync)=> {
-                if (!completer.isCompleted) {
-                    completer.complete();
-                }
-                
-                SchedulerBinding.instance.addPostFrameCallback((TimeSpan timeStamp)=> {
-                    stream.removeListener(listener);
-                });
-            },
-            onError: (Exception error) =>{
-                if (!completer.isCompleted) {
-                    completer.complete();
-                }
-                stream.removeListener(listener);
-                UIWidgetsError.reportError(new UIWidgetsErrorDetails(
-                    context: new ErrorDescription("image failed to precache"),
-                    library: "image resource service",
-                    silent: true));
+                (image, sync) => {
+                    if (!completer.isCompleted) {
+                        completer.complete();
+                    }
+
+                    SchedulerBinding.instance.addPostFrameCallback(timeStamp => {
+                        stream.removeListener(listener: listener);
+                    });
+                },
+                onError: error => {
+                    if (!completer.isCompleted) {
+                        completer.complete();
+                    }
+
+                    stream.removeListener(listener: listener);
+                    UIWidgetsError.reportError(new UIWidgetsErrorDetails(
+                        context: new ErrorDescription("image failed to precache"),
+                        library: "image resource service",
+                        silent: true));
-            stream.addListener(listener);
+            stream.addListener(listener: listener);
-            
         }
     }
 
 
     public delegate Widget ImageErrorWidgetBuilder(
         BuildContext context,
-        Object error,
+        object error,
+        public readonly AlignmentGeometry alignment;
+        public readonly Rect centerSlice;
+        public readonly Color color;
+        public readonly BlendMode colorBlendMode;
+        public readonly ImageErrorWidgetBuilder errorBuilder;
+        public readonly FilterQuality filterQuality;
+        public readonly BoxFit? fit;
+        public readonly ImageFrameBuilder frameBuilder;
+        public readonly bool gaplessPlayback;
+        public readonly float? height;
+
+        public readonly ImageProvider image;
+        public readonly ImageLoadingBuilder loadingBuilder;
+        public readonly bool matchTextDirection;
+        public readonly ImageRepeat repeat;
+        public readonly float? width;
+
         public Image(
             Key key = null,
             ImageProvider image = null,
             int? cacheWidth = null,
             int? cacheHeight = null
         ) {
-            var image = ResizeImage.resizeIfNeeded(cacheWidth, cacheHeight,
-                new NetworkImage(src, scale: scale, headers: headers));
+            var image = ResizeImage.resizeIfNeeded(cacheWidth: cacheWidth, cacheHeight: cacheHeight,
+                new NetworkImage(url: src, scale: scale, headers: headers));
             return new Image(
                 key: key,
                 image: image,
                 alignment: alignment,
                 repeat: repeat,
                 centerSlice: centerSlice,
-                matchTextDirection : matchTextDirection,
+                matchTextDirection: matchTextDirection,
                 gaplessPlayback: gaplessPlayback,
                 filterQuality: filterQuality
             );
             BlendMode colorBlendMode = BlendMode.srcIn,
             BoxFit? fit = null,
             AlignmentGeometry alignment = null,
-            ImageRepeat repeat = ImageRepeat.noRepeat, 
+            ImageRepeat repeat = ImageRepeat.noRepeat,
             bool matchTextDirection = false,
             Rect centerSlice = null,
             bool gaplessPlayback = false,
         ) {
-            var fileImage = ResizeImage.resizeIfNeeded(cacheWidth, cacheHeight, new FileImage(file, scale: scale));
+            var fileImage = ResizeImage.resizeIfNeeded(cacheWidth: cacheWidth, cacheHeight: cacheHeight,
+                new FileImage(file: file, scale: scale));
-                loadingBuilder: null,
+                null,
                 errorBuilder: errorBuilder,
                 width: width,
                 height: height,
         ) {
             var _scale = scale ?? 1.0f;
             var _image = scale != null
-                ? (AssetBundleImageProvider) new ExactAssetImage(name, bundle: bundle, scale: _scale)
-                : new AssetImage(name, bundle: bundle);
-            var _Image = ResizeImage.resizeIfNeeded(cacheWidth, cacheHeight, _image);
-            
+                ? (AssetBundleImageProvider) new ExactAssetImage(assetName: name, bundle: bundle, scale: _scale)
+                : new AssetImage(assetName: name, bundle: bundle);
+            var _Image = ResizeImage.resizeIfNeeded(cacheWidth: cacheWidth, cacheHeight: cacheHeight, provider: _image);
+
-                loadingBuilder: null,
+                null,
                 errorBuilder: errorBuilder,
                 width: width,
                 height: height,
             int? cacheHeight = null
         ) {
             // ResizeImage.resizeIfNeeded(cacheWidth, cacheHeight, MemoryImage(bytes, scale: scale));
-            var memoryImage = new MemoryImage(bytes, scale);
+            var memoryImage = new MemoryImage(bytes: bytes, scale: scale);
-                image: ResizeImage.resizeIfNeeded(cacheWidth, cacheHeight, new MemoryImage(bytes, scale: scale)),
+                ResizeImage.resizeIfNeeded(cacheWidth: cacheWidth, cacheHeight: cacheHeight,
+                    new MemoryImage(bytes: bytes, scale: scale)),
-                loadingBuilder: null,
+                null,
                 errorBuilder: errorBuilder,
                 width: width,
                 height: height,
                 alignment: alignment,
                 repeat: repeat,
                 centerSlice: centerSlice,
-                matchTextDirection : matchTextDirection,
+                matchTextDirection: matchTextDirection,
-        public readonly ImageProvider image;
-        public readonly ImageFrameBuilder frameBuilder;
-        public readonly ImageLoadingBuilder loadingBuilder;
-        public readonly ImageErrorWidgetBuilder errorBuilder;
-        public readonly float? width;
-        public readonly float? height;
-        public readonly Color color;
-        public readonly FilterQuality filterQuality;
-        public readonly BlendMode colorBlendMode;
-        public readonly BoxFit? fit;
-        public readonly AlignmentGeometry alignment;
-        public readonly ImageRepeat repeat;
-        public readonly Rect centerSlice;
-        public readonly bool gaplessPlayback;
-        public readonly bool matchTextDirection;
-
-            base.debugFillProperties(properties);
+            base.debugFillProperties(properties: properties);
-            properties.add(new DiagnosticsProperty<ImageProvider>("image", image));
-            properties.add(new DiagnosticsProperty<ImageFrameBuilder>("frameBuilder", frameBuilder));
-            properties.add(new DiagnosticsProperty<ImageLoadingBuilder>("loadingBuilder", loadingBuilder));
-            properties.add(new FloatProperty("width", width, defaultValue: foundation_.kNullDefaultValue));
-            properties.add(new FloatProperty("height", height, defaultValue: foundation_.kNullDefaultValue));
-            properties.add(new ColorProperty("color", color,
+            properties.add(new DiagnosticsProperty<ImageProvider>("image", value: image));
+            properties.add(new DiagnosticsProperty<ImageFrameBuilder>("frameBuilder", value: frameBuilder));
+            properties.add(new DiagnosticsProperty<ImageLoadingBuilder>("loadingBuilder", value: loadingBuilder));
+            properties.add(new FloatProperty("width", value: width, defaultValue: foundation_.kNullDefaultValue));
+            properties.add(new FloatProperty("height", value: height, defaultValue: foundation_.kNullDefaultValue));
+            properties.add(new ColorProperty("color", value: color,
-            properties.add(new EnumProperty<BlendMode>("colorBlendMode", colorBlendMode,
+            properties.add(new EnumProperty<BlendMode>("colorBlendMode", value: colorBlendMode,
-            properties.add(new EnumProperty<BoxFit?>("fit", fit, defaultValue: foundation_.kNullDefaultValue));
-            properties.add(new DiagnosticsProperty<AlignmentGeometry>("alignment", alignment,
+            properties.add(new EnumProperty<BoxFit?>("fit", value: fit, defaultValue: foundation_.kNullDefaultValue));
+            properties.add(new DiagnosticsProperty<AlignmentGeometry>("alignment", value: alignment,
+                defaultValue: foundation_.kNullDefaultValue));
+            properties.add(new EnumProperty<ImageRepeat>("repeat", value: repeat, defaultValue: ImageRepeat.noRepeat));
+            properties.add(new DiagnosticsProperty<Rect>("centerSlice", value: centerSlice,
-            properties.add(new EnumProperty<ImageRepeat>("repeat", repeat, defaultValue: ImageRepeat.noRepeat));
-            properties.add(new DiagnosticsProperty<Rect>("centerSlice", centerSlice,
+            properties.add(new EnumProperty<FilterQuality>("filterQuality", value: filterQuality,
-            properties.add(new EnumProperty<FilterQuality>("filterQuality", filterQuality,
-                foundation_.kNullDefaultValue));
-            properties.add(new FlagProperty("matchTextDirection", value: matchTextDirection, ifTrue: "match text direction"));
+            properties.add(new FlagProperty("matchTextDirection", value: matchTextDirection, "match text direction"));
-        ImageStream _imageStream;
+        int _frameNumber;
+        ImageStream _imageStream;
+        bool _invertColors;
+        bool _isListeningToStream;
+        object _lastException;
+        StackTrace _lastStack;
-        bool _isListeningToStream = false;
-        bool _invertColors;
-        int _frameNumber;
-        bool _wasSynchronouslyLoaded;
-        Object _lastException;
-        StackTrace _lastStack;
+        bool _wasSynchronouslyLoaded;
+
+
+        public void didChangeAccessibilityFeatures() {
+            setState(() => { _updateInvertColors(); });
+        }
+
+
+        public void didChangeMetrics() {
+            setState();
+        }
+
+        public void didChangeTextScaleFactor() {
+            setState();
+        }
+
+        public void didChangePlatformBrightness() {
+            setState();
+        }
+
+        public void didChangeLocales(List<Locale> locale) {
+            setState();
+        }
+
+        public Future<bool> didPopRoute() {
+            return Future.value(false).to<bool>();
+        }
+
+        public Future<bool> didPushRoute(string route) {
+            return Future.value(false).to<bool>();
+        }
 
         public override void initState() {
             base.initState();
             _updateInvertColors();
             _resolveImage();
 
-            if (TickerMode.of(context)) {
+            if (TickerMode.of(context: context)) {
                 _listenToStream();
             }
             else {
         }
 
         public override void didUpdateWidget(StatefulWidget oldWidget) {
-            base.didUpdateWidget(oldWidget);
-            Image image = (Image) oldWidget;
+            base.didUpdateWidget(oldWidget: oldWidget);
+            var image = (Image) oldWidget;
-                (widget.loadingBuilder == null) != (image.loadingBuilder == null)) {
-                _imageStream.removeListener(_getListener(image.loadingBuilder));
+                widget.loadingBuilder == null != (image.loadingBuilder == null)) {
+                _imageStream.removeListener(_getListener(loadingBuilder: image.loadingBuilder));
                 _imageStream.addListener(_getListener());
             }
 
         }
 
-
-        public void didChangeAccessibilityFeatures() {
-            setState(() => {
-                _updateInvertColors();
-            });
-        }
         public override void reassemble() {
             _resolveImage(); // in case the image cache was flushed
             base.reassemble();
         void _updateInvertColors() {
-            _invertColors = MediaQuery.of(context, nullOk: true)?.invertColors
+            _invertColors = MediaQuery.of(context: context, true)?.invertColors
-            ScrollAwareImageProvider<object> provider = new ScrollAwareImageProvider<object>(
+            //TODO: why refactoring this code? we need a PR to fix it!
+            /*ScrollAwareImageProvider<object> provider = new ScrollAwareImageProvider<object>(
-                imageProvider: (ImageProvider<object>)widget.image
-            );
-            ImageStream newStream =
-                provider.resolve(ImageUtils.createLocalImageConfiguration(
-                    context,
-                    size: widget.width != null && widget.height != null
-                        ? new Size(widget.width.Value, widget.height.Value)
+                imageProvider: widget.image);*/
+            var newStream =
+                widget.image.resolve(ImageUtils.createLocalImageConfiguration(
+                    context: context,
+                    widget.width != null && widget.height != null
+                        ? new Size(width: widget.width.Value, height: widget.height.Value)
-            _updateSourceStream(newStream);
+            _updateSourceStream(newStream: newStream);
         }
 
         void _onError(Exception error) {
 
             ImageErrorListener onError = null;
             if (widget.errorBuilder != null) {
-                onError = (Exception error) => {
+                onError = error => {
                     setState(() => {
                         _lastException = error;
                         // _lastStack = stackTrace;
 
             return new ImageStreamListener(
-                _handleImageFrame,
+                onImage: _handleImageFrame,
                 onChunk: onChunk,
                 onError: onError
             );
                 setState(() => { _imageInfo = null; });
             }
 
-            setState(()=> {
+            setState(() => {
                 _loadingProgress = null;
                 _frameNumber = 0;
                 _wasSynchronouslyLoaded = false;
-            if (_isListeningToStream)
+            if (_isListeningToStream) {
+            }
         }
 
         void _listenToStream() {
         public override Widget build(BuildContext context) {
             if (_lastException != null) {
                 D.assert(widget.errorBuilder != null);
-                return widget.errorBuilder(context, _lastException, _lastStack);
+                return widget.errorBuilder(context: context, error: _lastException, stackTrace: _lastStack);
             }
 
             Widget image = new RawImage(
                 invertColors: _invertColors,
                 filterQuality: widget.filterQuality
             );
-            if (widget.frameBuilder != null)
-                image = widget.frameBuilder(context, image, _frameNumber, _wasSynchronouslyLoaded);
+            if (widget.frameBuilder != null) {
+                image = widget.frameBuilder(context: context, child: image, frame: _frameNumber,
+                    wasSynchronouslyLoaded: _wasSynchronouslyLoaded);
+            }
-            if (widget.loadingBuilder != null)
-                image = widget.loadingBuilder(context, image, _loadingProgress);
+            if (widget.loadingBuilder != null) {
+                image = widget.loadingBuilder(context: context, child: image, loadingProgress: _loadingProgress);
+            }
-            base.debugFillProperties(description);
-            description.add(new DiagnosticsProperty<ImageStream>("stream", _imageStream));
-            description.add(new DiagnosticsProperty<ImageInfo>("pixels", _imageInfo));
-            description.add(new DiagnosticsProperty<ImageChunkEvent>("loadingProgress", _loadingProgress));
-            description.add(new DiagnosticsProperty<int>("frameNumber", _frameNumber));
-            description.add(new DiagnosticsProperty<bool>("wasSynchronouslyLoaded", _wasSynchronouslyLoaded));
-        }
-
-
-        public void didChangeMetrics() {
-            setState();
-        }
-
-        public void didChangeTextScaleFactor() {
-            setState();
-        }
-
-        public void didChangePlatformBrightness() {
-            setState();
-        }
-
-        public void didChangeLocales(List<Locale> locale) {
-            setState();
-        }
-
-        public Future<bool> didPopRoute() {
-            return Future.value(false).to<bool>();
-        }
-
-        public Future<bool> didPushRoute(string route) {
-            return Future.value(false).to<bool>();
+            base.debugFillProperties(properties: description);
+            description.add(new DiagnosticsProperty<ImageStream>("stream", value: _imageStream));
+            description.add(new DiagnosticsProperty<ImageInfo>("pixels", value: _imageInfo));
+            description.add(new DiagnosticsProperty<ImageChunkEvent>("loadingProgress", value: _loadingProgress));
+            description.add(new DiagnosticsProperty<int>("frameNumber", value: _frameNumber));
+            description.add(new DiagnosticsProperty<bool>("wasSynchronouslyLoaded", value: _wasSynchronouslyLoaded));
         }
     }
 }

com.unity.uiwidgets/Runtime/widgets/localizations.cs

 using System.Collections.Generic;
 using System.Linq;
 using Unity.UIWidgets.async2;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.rendering;
 using Unity.UIWidgets.ui;
             if (pendingList == null) {
                 return new SynchronousFuture<Dictionary<Type, object>>(output);
             }
-
-            return Future.wait<object>(pendingList.Select(p => p.futureValue))
+            return Future.wait<object>(LinqUtils<Future<object>, _Pending>.SelectList(pendingList, (p => p.futureValue)))
                 .then(values => {
                     
                     var list = (List<object>)values;

com.unity.uiwidgets/Runtime/widgets/navigator.cs

 using System.Collections.Generic;
 using System.Linq;
 using Unity.UIWidgets.async2;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.external.simplejson;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 
             if (initialRoute != null) {
                 _history.AddRange(
-                    widget.onGenerateInitialRoutes(
+                    LinqUtils<_RouteEntry,Route>.SelectList(
+                        widget.onGenerateInitialRoutes(
-                        widget.initialRoute ?? Navigator.defaultRouteName
-                    ).Select((Route route) =>
-                            new _RouteEntry(
-                                route,
-                                initialState: _RouteLifecycle.add
-                            )
-                    )
-                );
+                                widget.initialRoute ?? Navigator.defaultRouteName
+                ), (Route route) =>
+                         new _RouteEntry(
+                             route, 
+                             initialState: _RouteLifecycle.add
+                             )
+                        )
+                    );
             }
             D.assert(!_debugLocked);
             D.assert(() => {
 
         public Future<bool> maybePop<T>(T result = default(T)) {
             ///asyn
-            _RouteEntry lastEntry = null; //_history.Where(_RouteEntry.isPresentPredicate);
+            _RouteEntry lastEntry = null; 
             foreach (_RouteEntry routeEntry in _history) {
                 if (_RouteEntry.isPresentPredicate(routeEntry)) {
                     lastEntry = routeEntry;

com.unity.uiwidgets/Runtime/widgets/page_storage.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 
 namespace Unity.UIWidgets.widgets {
         }
 
         public override string ToString() {
-            return $"StorageEntryIdentifier({string.Join(":", keys.Select(x => x.ToString()).ToArray())})";
+            return $"StorageEntryIdentifier({string.Join(":", LinqUtils<string, PageStorageKey>.SelectList(keys, (x => x.ToString())))})";
         }
 
         public bool Equals(_StorageEntryIdentifier other) {

com.unity.uiwidgets/Runtime/widgets/shortcuts.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Runtime.CompilerServices;
+using Unity.UIWidgets.external;
+    public class KeySet<T> : KeyboardKey, IEquatable<KeySet<T>> {
+        public static readonly List<int> _tempHashStore3 = new List<int> {0, 0, 0}; // used to sort exactly 3 keys
+        public static readonly List<int> _tempHashStore4 = new List<int> {0, 0, 0, 0}; // used to sort exactly 4 keys
+        public readonly HashSet<T> _keys;
-    public class KeySet<T> : KeyboardKey, IEquatable<KeySet<T>> 
-    {  
+        public int _hashCode;
+
-            T key2 = default(T),
-            T key3 = default(T),
-            T key4 = default(T)
+            T key2 = default,
+            T key3 = default,
+            T key4 = default
-            _keys.Add(key1);
-            int count = 1;
+            _keys.Add(item: key1);
+            var count = 1;
-                _keys.Add(key2);
+                _keys.Add(item: key2);
                 D.assert(() => {
                     count++;
                     return true;
             if (key3 != null) {
-                _keys.Add(key3);
+                _keys.Add(item: key3);
                 D.assert(() => {
                     count++;
                     return true;
             if (key4 != null) {
-                _keys.Add(key4);
+                _keys.Add(item: key4);
                 D.assert(() => {
                     count++;
                     return true;
                 () => "Two or more provided keys are identical. Each key must appear only once.");
         }
 
-        public KeySet (HashSet<T> keys) 
-        {
+        public KeySet(HashSet<T> keys) {
-            D.assert(keys.isNotEmpty);
-            D.assert(!keys.Contains(default(T)));
+            D.assert(result: keys.isNotEmpty);
+            D.assert(!keys.Contains(default));
-                _keys.Add(key);
+                _keys.Add(item: key);
-            
-        public HashSet<T> keys 
-        {
-            get { return new HashSet<T>(_keys); }
+        public HashSet<T> keys {
+            get { return new HashSet<T>(collection: _keys); }
-        public readonly HashSet<T> _keys;
-        
-        
-        public static readonly List<int> _tempHashStore3 = new List<int>() {0, 0, 0}; // used to sort exactly 3 keys
-        public static readonly List<int> _tempHashStore4 = new List<int>() {0, 0, 0, 0}; // used to sort exactly 4 keys
-        
-        public int _hashCode;
-        public bool Equals(KeySet<T> other)
-        {
-            if (ReferenceEquals(null, other)) {
+        public bool Equals(KeySet<T> other) {
+            if (ReferenceEquals(null, objB: other)) {
-            if (ReferenceEquals(this, other)) {
+            if (ReferenceEquals(this, objB: other)) {
-            return Equals(_keys, other._keys) && _hashCode == other._hashCode;
+            return Equals(objA: _keys, objB: other._keys) && _hashCode == other._hashCode;
-        public override bool Equals(object obj)
-        {
-            if (ReferenceEquals(null, obj)) {
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, objB: obj)) {
-            if (ReferenceEquals(this, obj)) {
+            if (ReferenceEquals(this, objB: obj)) {
                 return true;
             }
 
             return Equals((KeySet<T>) obj);
         }
 
-        public override int GetHashCode()
-        {
-            unchecked
-            {
+        public override int GetHashCode() {
+            unchecked {
-                int length = _keys.Count;
+                var length = _keys.Count;
-                int h1 = iterator.GetHashCode();
+                var h1 = iterator.GetHashCode();
 
                 if (length == 1) {
                     // Don't do anything fancy if there's exactly one key.
                 iterator.MoveNext();
-                int h2 = iterator.GetHashCode();
+                var h2 = iterator.GetHashCode();
                 if (length == 2) {
                     // No need to sort if there's two keys, just compare them.
                     return _hashCode = h1 < h2
 
                 // Sort key hash codes and feed to hashList to ensure the aggregate
                 // hash code does not depend on the key order.
-                List<int> sortedHashes = length == 3
+                var sortedHashes = length == 3
                     ? _tempHashStore3
                     : _tempHashStore4;
                 sortedHashes[0] = h1;
                     iterator.MoveNext();
                     sortedHashes[3] = iterator.GetHashCode();
                 }
+
-                return _hashCode  = (_hashCode * 397) ^ (sortedHashes != null ? sortedHashes.GetHashCode() : 0); 
+                return _hashCode = (_hashCode * 397) ^ (sortedHashes != null ? sortedHashes.GetHashCode() : 0);
+
-            return Equals(left, right);
+            return Equals(objA: left, objB: right);
-            return !Equals(left, right);
+            return !Equals(objA: left, objB: right);
-
-    
+
+        public static readonly HashSet<LogicalKeyboardKey> _modifiers = new HashSet<LogicalKeyboardKey> {
+            LogicalKeyboardKey.alt,
+            LogicalKeyboardKey.control,
+            LogicalKeyboardKey.meta,
+            LogicalKeyboardKey.shift
+        };
 
         public LogicalKeySet(
             LogicalKeyboardKey key1,
-        ) : base(key1: key1, key2: key2, key3: key3, key4: key4){ }
-        
-        public LogicalKeySet(HashSet<LogicalKeyboardKey> keys) : base(keys) { }
+        ) : base(key1: key1, key2: key2, key3: key3, key4: key4) {
+        }
-        public static readonly HashSet<LogicalKeyboardKey> _modifiers = new HashSet<LogicalKeyboardKey>(){
-            LogicalKeyboardKey.alt,
-            LogicalKeyboardKey.control,
-            LogicalKeyboardKey.meta,
-            LogicalKeyboardKey.shift,
-        };
+        public LogicalKeySet(HashSet<LogicalKeyboardKey> keys) : base(keys: keys) {
+        }
-        public string debugDescribeKeys() { 
-            List<LogicalKeyboardKey> sortedKeys = keys.ToList();
+        public string debugDescribeKeys() {
+            var sortedKeys = keys.ToList();
-             (LogicalKeyboardKey a, LogicalKeyboardKey b) => { 
-                 bool aIsModifier = a.synonyms.isNotEmpty() || _modifiers.Contains(a);
-                 bool bIsModifier = b.synonyms.isNotEmpty() || _modifiers.Contains(b);
-                 if (aIsModifier && !bIsModifier) {
-                     return -1;
-                 } else if (bIsModifier && !aIsModifier) {
-                     return 1;
-                 }
-                 return a.debugName.CompareTo(b.debugName); 
-             }
-            ); 
-            var results = sortedKeys.Select((LogicalKeyboardKey key) => key.debugName.ToString());
-            return string.Join(" + ",results);
-         
-      }
-      
-      
-      public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-        base.debugFillProperties(properties);
-        properties.add(new DiagnosticsProperty<HashSet<LogicalKeyboardKey>>("keys", _keys, description: debugDescribeKeys()));
-      }
+                (a, b) => {
+                    var aIsModifier = a.synonyms.isNotEmpty() || _modifiers.Contains(item: a);
+                    var bIsModifier = b.synonyms.isNotEmpty() || _modifiers.Contains(item: b);
+                    if (aIsModifier && !bIsModifier) {
+                        return -1;
+                    }
+
+                    if (bIsModifier && !aIsModifier) {
+                        return 1;
+                    }
+
+                    return a.debugName.CompareTo(strB: b.debugName);
+                }
+            );
+            var results = LinqUtils<string, LogicalKeyboardKey>.SelectList(sortedKeys, (key => key.debugName));
+            return string.Join(" + ", values: results);
+        }
+
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties: properties);
+            properties.add(
+                new DiagnosticsProperty<HashSet<LogicalKeyboardKey>>("keys", value: _keys, debugDescribeKeys()));
+        }
-    
+
-
-            object defaultValue =  null,
+            object defaultValue = null,
-                name: name,
-                value: value,
-                showName: showName,
-                defaultValue: defaultValue ?? foundation_.kNoDefaultValue,
-                level: level,
-                description: description
-            ) 
-            {
-               
-            }
+            name: name,
+            value: value,
+            showName: showName,
+            defaultValue: defaultValue ?? foundation_.kNoDefaultValue,
+            level: level,
+            description: description
+        ) {
+        }
-    
-        protected override string valueToString( TextTreeConfiguration parentConfiguration = null) {
-            
-            List<string> res = new List<string>();
+
+        protected override string valueToString(TextTreeConfiguration parentConfiguration = null) {
+            var res = new List<string>();
-                string temp = "{" + key.debugDescribeKeys() + "}:" + value[key];
-                res.Add(temp);
+                var temp = "{" + key.debugDescribeKeys() + "}:" + value[key: key];
+                res.Add(item: temp);
-            return string.Join(", ", res);
+
+            return string.Join(", ", values: res);
-    
+
+        public readonly bool modal;
-      public ShortcutManager(
-        Dictionary<LogicalKeySet, Intent> shortcuts = null,
-        bool modal = false
-      ) {
-          shortcuts = shortcuts ?? new Dictionary<LogicalKeySet, Intent>();
-          this.modal = modal;
-          this.shortcuts = shortcuts;
+
+        Dictionary<LogicalKeySet, Intent> _shortcuts;
+
+        public ShortcutManager(
+            Dictionary<LogicalKeySet, Intent> shortcuts = null,
+            bool modal = false
+        ) {
+            shortcuts = shortcuts ?? new Dictionary<LogicalKeySet, Intent>();
+            this.modal = modal;
+            this.shortcuts = shortcuts;
-      public readonly bool modal;
+        public Dictionary<LogicalKeySet, Intent> shortcuts {
+            get { return _shortcuts; }
+            set {
+                _shortcuts = value;
+                notifyListeners();
+            }
+        }
-      Dictionary<LogicalKeySet, Intent> _shortcuts;
-    
-      public Dictionary<LogicalKeySet, Intent>  shortcuts {
-          get { return _shortcuts; }
-          set {
-              _shortcuts = value;
-              notifyListeners();
-          }
-      }
+        public bool handleKeypress(
+            BuildContext context,
+            RawKeyEvent rawKeyEvent,
+            LogicalKeySet keysPressed = null
+        ) {
+            if (!(rawKeyEvent is RawKeyDownEvent)) {
+                return false;
+            }
-      
-      public bool handleKeypress(
-        BuildContext context,
-        RawKeyEvent rawKeyEvent,
-        LogicalKeySet keysPressed = null
-      ) {
-        if (!(rawKeyEvent is RawKeyDownEvent)) {
-          return false;
-        }
-        D.assert(context != null);
-        LogicalKeySet keySet = keysPressed ?? new LogicalKeySet(RawKeyboard.instance.keysPressed);
-        Intent matchedIntent = _shortcuts[keySet];
-        if (matchedIntent == null) {
-         
-          HashSet<LogicalKeyboardKey> pseudoKeys = new HashSet<LogicalKeyboardKey>{};
-          foreach (LogicalKeyboardKey setKey in keySet.keys) {
-            HashSet<LogicalKeyboardKey> synonyms = setKey.synonyms;
-            if (synonyms.isNotEmpty()) {
+            D.assert(context != null);
+            //FIX ME !
+            //Since we process key event produced by Unity instead of raw input info (physical key)  from os directly,
+            //we cannot handle the shortcut key press as in original flutter code
+            //TODO: however, we need find out a way to make this work in another way
+            return false;
+
+            /*
+            LogicalKeySet keySet = keysPressed ?? new LogicalKeySet(RawKeyboard.instance.keysPressed);
+            Intent matchedIntent = _shortcuts[keySet];
+            if (matchedIntent == null) {
-              pseudoKeys.Add(synonyms.First());
-            } else {
-              pseudoKeys.Add(setKey);
+              HashSet<LogicalKeyboardKey> pseudoKeys = new HashSet<LogicalKeyboardKey>{};
+              foreach (LogicalKeyboardKey setKey in keySet.keys) {
+                HashSet<LogicalKeyboardKey> synonyms = setKey.synonyms;
+                if (synonyms.isNotEmpty()) {
+                 
+                  pseudoKeys.Add(synonyms.First());
+                } else {
+                  pseudoKeys.Add(setKey);
+                }
+              }
+              matchedIntent = _shortcuts[new LogicalKeySet(pseudoKeys)];
-          }
-          matchedIntent = _shortcuts[new LogicalKeySet(pseudoKeys)];
-        }
-        if (matchedIntent != null) {
-          BuildContext primaryContext = FocusManagerUtils.primaryFocus?.context;
-          if (primaryContext == null) {
+            if (matchedIntent != null) {
+              BuildContext primaryContext = FocusManagerUtils.primaryFocus?.context;
+              if (primaryContext == null) {
+                return false;
+              }
+              return Actions.invoke(primaryContext, matchedIntent, nullOk: true);
+            }
+            
-          }
-          return Actions.invoke(primaryContext, matchedIntent, nullOk: true);
+            */
-        return false;
-      }
-      public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-          base.debugFillProperties(properties: properties);
-          properties.add(new DiagnosticsProperty<Dictionary<LogicalKeySet, Intent>>("shortcuts", _shortcuts));
-          properties.add(new FlagProperty("modal", value: modal, ifTrue: "modal", defaultValue: false));
-      }
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties: properties);
+            properties.add(new DiagnosticsProperty<Dictionary<LogicalKeySet, Intent>>("shortcuts", value: _shortcuts));
+            properties.add(new FlagProperty("modal", value: modal, "modal", defaultValue: false));
+        }
-      
+
-      
-      public Shortcuts(
-        Key key = null,
-        ShortcutManager manager = null,
-        Dictionary<LogicalKeySet, Intent> shortcuts = null,
-        Widget child = null,
-        string debugLabel = null
-      ) : base(key: key) {
-          this.manager = manager;
-          this.shortcuts = shortcuts;
-          this.child = child;
-          this.debugLabel = debugLabel;
-      }
-      
-      public readonly ShortcutManager manager;
-      
-      public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
-      
-      public readonly Widget child;
-      
-      public readonly string debugLabel;
+        public readonly Widget child;
-      public static ShortcutManager of(BuildContext context, bool nullOk = false) {
-        D.assert(context != null);
-        _ShortcutsMarker inherited = context.dependOnInheritedWidgetOfExactType<_ShortcutsMarker>();
-        D.assert(() => {
-          if (nullOk) {
-            return true;
-          }
-          if (inherited == null) {
-            throw new UIWidgetsError($"Unable to find a {typeof(Shortcuts)} widget in the context.\n" +
-                $"{typeof(Shortcuts)}.of()was called with a context that does not contain a " +
-                $"{typeof(Shortcuts)} widget.\n" +
-                $"No {typeof(Shortcuts)} ancestor could be found starting from the context that was " +
-                $"passed to {typeof(Shortcuts)}.of().\n" +
-                "The context used was:\n" +
-                $"  {context}");
-          }
-          return true;
-        });
-        return inherited?.notifier;
-      }
+        public readonly string debugLabel;
-      
-      public override State createState() {
-          return new _ShortcutsState();
-      }
+        public readonly ShortcutManager manager;
+        public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
-      public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-        base.debugFillProperties(properties);
-        properties.add(new DiagnosticsProperty<ShortcutManager>("manager", manager, defaultValue: null));
-        properties.add(new ShortcutMapProperty("shortcuts", shortcuts, description: debugLabel?.isNotEmpty() ?? false ? debugLabel : null));
-      }
+        public Shortcuts(
+            Key key = null,
+            ShortcutManager manager = null,
+            Dictionary<LogicalKeySet, Intent> shortcuts = null,
+            Widget child = null,
+            string debugLabel = null
+        ) : base(key: key) {
+            this.manager = manager;
+            this.shortcuts = shortcuts;
+            this.child = child;
+            this.debugLabel = debugLabel;
+        }
+
+        public static ShortcutManager of(BuildContext context, bool nullOk = false) {
+            D.assert(context != null);
+            var inherited = context.dependOnInheritedWidgetOfExactType<_ShortcutsMarker>();
+            D.assert(() => {
+                if (nullOk) {
+                    return true;
+                }
+
+                if (inherited == null) {
+                    throw new UIWidgetsError($"Unable to find a {typeof(Shortcuts)} widget in the context.\n" +
+                                             $"{typeof(Shortcuts)}.of()was called with a context that does not contain a " +
+                                             $"{typeof(Shortcuts)} widget.\n" +
+                                             $"No {typeof(Shortcuts)} ancestor could be found starting from the context that was " +
+                                             $"passed to {typeof(Shortcuts)}.of().\n" +
+                                             "The context used was:\n" +
+                                             $"  {context}");
+                }
+
+                return true;
+            });
+            return inherited?.notifier;
+        }
+
+
+        public override State createState() {
+            return new _ShortcutsState();
+        }
+
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties: properties);
+            properties.add(new DiagnosticsProperty<ShortcutManager>("manager", value: manager, defaultValue: null));
+            properties.add(new ShortcutMapProperty("shortcuts", value: shortcuts,
+                description: debugLabel?.isNotEmpty() ?? false ? debugLabel : null));
+        }
-        
-      private ShortcutManager _internalManager;
-      public ShortcutManager manager {
-          get { return widget.manager ?? _internalManager; }
-      }
-
-      
-      public override void dispose() {
-        _internalManager?.dispose();
-        base.dispose();
-      }
+        ShortcutManager _internalManager;
-      
-      public override void initState() {
-        base.initState();
-        if (widget.manager == null) {
-          _internalManager = new ShortcutManager();
+        public ShortcutManager manager {
+            get { return widget.manager ?? _internalManager; }
-        manager.shortcuts = widget.shortcuts;
-      }
-      
-      public override void didUpdateWidget(StatefulWidget oldWidget) {
-        base.didUpdateWidget((Shortcuts)oldWidget);
-        if (widget.manager != ((Shortcuts)oldWidget).manager) {
-          if (widget.manager != null) {
+
+        public override void dispose() {
-            _internalManager = null;
-          } else {
-            _internalManager = _internalManager?? new ShortcutManager();
-          }
+            base.dispose();
-        manager.shortcuts = widget.shortcuts;
-      }
-      public bool _handleOnKey(FocusNode node, RawKeyEvent _event)
-      {
-        if (node.context == null) {
-          return false;
+
+        public override void initState() {
+            base.initState();
+            if (widget.manager == null) {
+                _internalManager = new ShortcutManager();
+            }
+
+            manager.shortcuts = widget.shortcuts;
-        return manager.handleKeypress(node.context, _event) || manager.modal;
-      }
-      
-      public override Widget build(BuildContext context) {
-        return new Focus(
-          debugLabel: typeof(Shortcuts).ToString(),
-          canRequestFocus: false,
-          onKey: _handleOnKey,
-          child: new _ShortcutsMarker(
-            manager: manager,
-            child: widget.child
-          )
-        );
-      }
+
+
+        public override void didUpdateWidget(StatefulWidget oldWidget) {
+            base.didUpdateWidget((Shortcuts) oldWidget);
+            if (widget.manager != ((Shortcuts) oldWidget).manager) {
+                if (widget.manager != null) {
+                    _internalManager?.dispose();
+                    _internalManager = null;
+                }
+                else {
+                    _internalManager = _internalManager ?? new ShortcutManager();
+                }
+            }
+
+            manager.shortcuts = widget.shortcuts;
+        }
+
+        public bool _handleOnKey(FocusNode node, RawKeyEvent _event) {
+            if (node.context == null) {
+                return false;
+            }
+
+            return manager.handleKeypress(context: node.context, rawKeyEvent: _event) || manager.modal;
+        }
+
+        public override Widget build(BuildContext context) {
+            return new Focus(
+                debugLabel: typeof(Shortcuts).ToString(),
+                canRequestFocus: false,
+                onKey: _handleOnKey,
+                child: new _ShortcutsMarker(
+                    manager: manager,
+                    child: widget.child
+                )
+            );
+        }
     }
 
     public class _ShortcutsMarker : InheritedNotifier<ShortcutManager> {
             D.assert(child != null);
         }
     }
-    
 }

com.unity.uiwidgets/Runtime/widgets/sliver.cs

         }
 
         public override void debugVisitOnstageChildren(ElementVisitor visitor) {
-            _childElements.Values.Where(child => {
+            LinqUtils<Element>.WhereList(_childElements.Values, (child => {
                 SliverMultiBoxAdaptorParentData parentData =
                     (SliverMultiBoxAdaptorParentData) child.renderObject.parentData;
                 float itemExtent = 0;
                        parentData.layoutOffset < renderObject.constraints.scrollOffset + renderObject.constraints.remainingPaintExtent &&
                        parentData.layoutOffset + itemExtent > renderObject.constraints.scrollOffset;
 
-            }).ToList().ForEach(e => visitor(e));
+            })).ForEach(e => visitor(e));
         }
     }
 

com.unity.uiwidgets/Runtime/widgets/viewport.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.painting;
 using Unity.UIWidgets.rendering;
         ) : base(key: key, children: slivers) {
             D.assert(offset != null);
             D.assert(slivers != null);
-            D.assert(center == null || slivers.Where((Widget child) => child.key == center).Count() == 1);
+            D.assert(center == null || LinqUtils<Widget>.WhereList(slivers,((Widget child) => child.key == center)).Count() == 1);
             D.assert(cacheExtentStyle != null);
             D.assert(cacheExtentStyle != CacheExtentStyle.viewport || cacheExtent != null);
             this.axisDirection = axisDirection;
         }
 
         public override void debugVisitOnstageChildren(ElementVisitor visitor) {
-            children.Where(e => {
+            LinqUtils<Element>.WhereList(children, (e => {
-            }).ToList().ForEach(e => visitor(e));
+            })).ForEach(e => visitor(e));
         }
     }
 

com.unity.uiwidgets/Runtime/widgets/widget_inspector.cs

 using System.Linq;
 using System.Runtime.CompilerServices;
 using Unity.UIWidgets.async2;
+using Unity.UIWidgets.external;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.painting;
                 path = _getElementParentChain((Element)value, groupName);
             else
                 throw new UIWidgetsError(new List<DiagnosticsNode>{new ErrorSummary($"Cannot get parent chain for node of type {value.GetType()}")});
-
-            return path.Select(
-                    (_DiagnosticsPathNode node) => 
+            return LinqUtils<Dictionary<string, object>, _DiagnosticsPathNode>.SelectList(
+                path,((_DiagnosticsPathNode node) => 
-                ).ToList();
+                ));
         }
         Dictionary<string, object> _pathNodeToJson(_DiagnosticsPathNode pathNode, InspectorSerializationDelegate _delegate) {
             if (pathNode == null)
                 } 
             }
             if (isElement && isWidgetCreationTracked()) {
-                List<DiagnosticsNode> localNodes = nodes.Where((DiagnosticsNode node) =>
-                    _isValueCreatedByLocalProject(node.value)).ToList();
+                List<DiagnosticsNode> localNodes = LinqUtils<DiagnosticsNode>.WhereList(nodes,(DiagnosticsNode node) =>
+                    _isValueCreatedByLocalProject(node.value));
-            
-
             //return nodes.take(maxDescendentsTruncatableNode).toList();
             List<DiagnosticsNode> results = new List<DiagnosticsNode>();
             for (int i = 0; i < maxDescendentsTruncatableNode; i++) {
         }
         public override List<DiagnosticsNode> filterProperties(List<DiagnosticsNode> properties, DiagnosticsNode owner) { 
             bool createdByLocalProject = _nodesCreatedByLocalProject.Contains(owner);
-            return properties.Where((DiagnosticsNode node)=>{
+            return LinqUtils<DiagnosticsNode>.WhereList(properties,(DiagnosticsNode node)=>{
-            }).ToList();
+            });
         }
         public override List<DiagnosticsNode> truncateNodesList(List<DiagnosticsNode> nodes, DiagnosticsNode owner) {
             if (maxDescendentsTruncatableNode >= 0 &&
             }
 
             if (parameterLocations != null) {
-                json["parameterLocations"] = parameterLocations.Select(
-                    (_Location location) => location.toJsonMap()).ToList();
+                json["parameterLocations"] =
+                    LinqUtils<object, _Location>.SelectList(
+                        parameterLocations,((_Location location) => location.toJsonMap()));
             }
 
             return json;

engine/README.md

 ```
 cd $FLUTTER_ROOT
 ./flutter/tools/gn --unoptimized
-ninja -C out/android_debug_unopt/ flutter/third_party/txt:txt_lib
-If the compilation fails because "no available Mac SDK is found" (in flutter-1.17 the build tool will only try to find Mac 10.XX SDKs), please modify the file "/src/build/Mac/find_sdk.py" under flutter root by setting "sdks" as your current sdk, e.g., ['11.0']. 
+add this line to the end of out/host_debug_unopt/args.gn:
+```
+icu_use_data_file=false
+```
-### Prepare icu data (TODO: try to build it into the library directly!)
+finally run ninja:
+```
+ninja -C out/host_debug_unopt/ flutter/third_party/txt:txt_lib
+```
-move the built icu data file from $FLUTTER_ROOT/out/host_debug_unopt/icudtl.dat to the StreamingAssets path
+If the compilation fails because "no available Mac SDK is found" (in flutter-1.17 the build tool will only try to find Mac 10.XX SDKs), please modify the file "/src/build/Mac/find_sdk.py" under flutter root by setting "sdks" as your current sdk, e.g., ['11.0'].
+
 
 ### Creat symbolic
 
 
 ```
 cd <uiwidigets_dir>\engine
-mono bee.exe
+mono bee.exe mac
 ```
 
 

engine/src/shell/platform/unity/darwin/macos/uiwidgets_panel.mm

   args.struct_size = sizeof(UIWidgetsProjectArgs);
   args.assets_path = streaming_assets_path;
   args.font_asset = settings;
-  //TODO: not support icu yet
-  
-  std::string icu_path = std::string(streaming_assets_path) + "/icudtl.dat";
-  args.icu_data_path = icu_path.c_str();
   
   args.command_line_argc = 0;
   args.command_line_argv = nullptr;

Samples/UIWidgetsSamples_2019_4/Assets/MaterialSample/HoverSample.cs

+using Unity.UIWidgets.engine2;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.painting;
+using Unity.UIWidgets.widgets;
+using TextStyle = Unity.UIWidgets.painting.TextStyle;
+using ui_ = Unity.UIWidgets.widgets.ui_;
+using uiwidgets;
+using Unity.UIWidgets.gestures;
+using Unity.UIWidgets.material;
+using Color = Unity.UIWidgets.ui.Color;
+
+namespace UIWidgetsSample
+{
+  /**
+   *
+   * STILL NOT WORKING, THERE SHOULD BE A BUG. FIX IT !!!!
+   * 
+   */
+  public class HoverSample : UIWidgetsPanel
+  {
+    protected void OnEnable()
+    {
+      base.OnEnable();
+    }
+
+    protected override void main()
+    {
+      ui_.runApp(new MyApp());
+    }
+
+    class MyApp : StatelessWidget
+    {
+      public override Widget build(BuildContext context)
+      {
+        return new MaterialApp(
+          debugShowCheckedModeBanner: false,
+          title: "Flutter Demo",
+          home: new Scaffold(
+            appBar: new AppBar(title: new Text("good")),
+            body: new Center(
+              child: new MyStatefulWidget()
+            )
+          )
+        );
+      }
+    }
+
+    class MyStatefulWidget : StatefulWidget
+    {
+      public MyStatefulWidget(Key key = null) : base(key: key)
+      {
+      }
+
+      public override State createState() => new _MyStatefulWidgetState();
+    }
+
+    class _MyStatefulWidgetState : State<MyStatefulWidget>
+    {
+      Color textColor = Colors.blue;
+      int _enterCounter = 0;
+      int _exitCounter = 0;
+      float x = 0.0f;
+      float y = 0.0f;
+
+      void _incrementEnter(PointerEvent details)
+      {
+        UnityEngine.Debug.Log("enter");
+        setState(() => { _enterCounter++; });
+      }
+
+      void _incrementExit(PointerEvent details)
+      {
+        setState(() =>
+        {
+          textColor = Colors.blue;
+          _exitCounter++;
+        });
+      }
+
+      void _updateLocation(PointerEvent details)
+      {
+        setState(() =>
+        {
+          textColor = Colors.red;
+          x = details.position.dx;
+          y = details.position.dy;
+        });
+      }
+
+
+      public override Widget build(BuildContext context)
+      {
+        return new MouseRegion(
+          onEnter: _incrementEnter,
+          onHover: _updateLocation,
+          onExit: _incrementExit,
+          child: new FlatButton(
+            color: Colors.white,
+            textColor: Colors.teal[700], //when hovered text color change
+            shape: new RoundedRectangleBorder(
+              borderRadius: BorderRadius.circular(5),
+              side: new BorderSide(
+                color: Colors.teal[700]
+              )
+            ),
+            onPressed: () => { },
+            child: new Text("Log in", style: new TextStyle(color: textColor))
+          )
+        );
+      }
+    }
+  }
+}

com.unity.uiwidgets/Runtime/external/LinqUtils.cs

+using System.Collections.Generic;
+
+namespace Unity.UIWidgets.external
+{
+    public static class LinqUtils<T, S>
+    {
+        public delegate T CreateItem(S item);
+
+        public delegate bool FilterDict(S value);
+
+        public static List<T> SelectList(IEnumerable<S> items, CreateItem createItem)
+        {
+            if (items == null)
+                return null;
+            var results = new List<T>();
+            foreach (var item in items) results.Add(createItem(item));
+
+            return results;
+        }
+
+        public static T[] SelectArray(List<S> items, CreateItem createItem)
+        {
+            if (items == null)
+                return null;
+
+            var itemCount = items.Count;
+            var results = new T[itemCount];
+            for (var i= 0; i < itemCount; i++)
+            {
+                results[i] = createItem(items[i]);
+            }
+
+            return results;
+        }
+
+        public static Dictionary<T, S> SelectDictionary(IEnumerable<S> items, CreateItem createItem)
+        {
+            if (items == null)
+                return null;
+            var results = new Dictionary<T, S>();
+            foreach (var item in items) results.Add(createItem(item), item);
+            return results;
+        }
+
+        public static Dictionary<T, S> WhereDictionary(Dictionary<T, S> items, FilterDict filterDict)
+        {
+            if (items == null)
+                return null;
+            var results = new Dictionary<T, S>();
+            foreach (var item in items)
+                if (filterDict(item.Value))
+                    results.Add(item.Key, item.Value);
+            return results;
+        }
+    }
+
+    public static class LinqUtils<T>
+    {
+        public delegate T CreateItem(T item);
+
+        public delegate bool FilterItem(T item);
+
+        public static List<T> SelectList(IEnumerable<T> items, CreateItem createItem)
+        {
+            if (items == null)
+                return null;
+            var results = new List<T>();
+            foreach (var item in items) results.Add(createItem(item));
+
+            return results;
+        }
+
+        public static List<T> WhereList(IEnumerable<T> items, FilterItem filterItem)
+        {
+            if (items == null)
+                return null;
+            var results = new List<T>();
+            foreach (var item in items)
+                if (filterItem(item))
+                    results.Add(item);
+
+            return results;
+        }
+    }
+}