fix name space

com.unity.uiwidgets/Runtime/async/async_cast.cs

 using System;
-using System.Data.Common;
-using System.Runtime.Versioning;
+namespace Unity.UIWidgets.async {
+    public class CastStream<S, T> : Stream<T> {
+        readonly Stream<S> _source;
-public class CastStream<S, T> : Stream<T> {
-    readonly Stream<S> _source;
+        public CastStream(Stream<S> _source) {
+            this._source = _source;
+        }
-    public CastStream(Stream<S> _source) {
-        this._source = _source;
-    }
+        bool isBroadcast {
+            get { return _source.isBroadcast; }
+        }
-    bool isBroadcast {
-        get { return _source.isBroadcast; }
-    }
+        public override StreamSubscription<T> listen(Action<T> onData, Action<object, string> onError = null,
+            Action onDone = null, bool cancelOnError = false) {
+            var result = new CastStreamSubscription<S, T>(
+                _source.listen(null, onDone: onDone, cancelOnError: cancelOnError));
-    public override StreamSubscription<T> listen(Action<T> onData, Action<object, string> onError = null,
-        Action onDone = null, bool cancelOnError = false) {
-        var result = new CastStreamSubscription<S, T>(
-            _source.listen(null, onDone: onDone, cancelOnError: cancelOnError));
+            result.onData(onData);
+            result.onError(onError);
+            return result;
+        }
-        result.onData(onData);
-        result.onError(onError);
-        return result;
+        Stream<R> cast<R>() where R : class => new CastStream<S, R>(_source);
-    Stream<R> cast<R>() where R : class => new CastStream<S, R>(_source);
-}
+    class CastStreamSubscription<S, T> : StreamSubscription<T> {
+        readonly StreamSubscription<S> _source;
-class CastStreamSubscription<S, T> : StreamSubscription<T> {
-    readonly StreamSubscription<S> _source;
+        /// Zone where listen was called.
+        readonly Zone _zone = Zone.current;
-    /// Zone where listen was called.
-    readonly Zone _zone = Zone.current;
+        /// User's data handler. May be null.
+        ZoneUnaryCallback _handleData;
-    /// User's data handler. May be null.
-    ZoneUnaryCallback _handleData;
+        /// Copy of _source's handleError so we can report errors in onData.
+        /// May be null.
+        ZoneBinaryCallback _handleError;
-    /// Copy of _source's handleError so we can report errors in onData.
-    /// May be null.
-    ZoneBinaryCallback _handleError;
+        public CastStreamSubscription(StreamSubscription<S> _source) {
+            this._source = _source;
+            _source.onData(_onData);
+        }
-    public CastStreamSubscription(StreamSubscription<S> _source) {
-        this._source = _source;
-        _source.onData(_onData);
-    }
+        public override Future cancel() => _source.cancel();
-    public override Future cancel() => _source.cancel();
-
-    public override void onData(Action<T> handleData) {
-        _handleData = handleData == null
-            ? null
-            : _zone.registerUnaryCallback(data => {
-                handleData((T) data);
-                return null;
-            });
-    }
-
-    public override void onError(Action<object, string> handleError) {
-        _source.onError(handleError);
-        if (handleError == null) {
-            _handleError = null;
-        }
-        else {
-            _handleError = _zone
-                .registerBinaryCallback((a, b) => {
-                    handleError(a, (string) b);
+        public override void onData(Action<T> handleData) {
+            _handleData = handleData == null
+                ? null
+                : _zone.registerUnaryCallback(data => {
+                    handleData((T) data);
-    }
-    public override void onDone(Action handleDone) {
-        _source.onDone(handleDone);
-    }
+        public override void onError(Action<object, string> handleError) {
+            _source.onError(handleError);
+            if (handleError == null) {
+                _handleError = null;
+            }
+            else {
+                _handleError = _zone
+                    .registerBinaryCallback((a, b) => {
+                        handleError(a, (string) b);
+                        return null;
+                    });
+            }
+        }
-    void _onData(S data) {
-        if (_handleData == null) return;
-        T targetData;
-        try {
-            // siyao: this might go wrong
-            targetData = (T) (object) data;
+        public override void onDone(Action handleDone) {
+            _source.onDone(handleDone);
-        catch (Exception error) {
-            if (_handleError == null) {
-                _zone.handleUncaughtError(error);
+
+        void _onData(S data) {
+            if (_handleData == null) return;
+            T targetData;
+            try {
+                // siyao: this might go wrong
+                targetData = (T) (object) data;
-            else {
-                _zone.runBinaryGuarded(_handleError, error, error.StackTrace);
+            catch (Exception error) {
+                if (_handleError == null) {
+                    _zone.handleUncaughtError(error);
+                }
+                else {
+                    _zone.runBinaryGuarded(_handleError, error, error.StackTrace);
+                }
+
+                return;
-            return;
+            _zone.runUnaryGuarded(_handleData, targetData);
-        _zone.runUnaryGuarded(_handleData, targetData);
-    }
+        public override void pause(Future resumeSignal = null) {
+            _source.pause(resumeSignal);
+        }
-    public override void pause(Future resumeSignal = null) {
-        _source.pause(resumeSignal);
-    }
+        public override void resume() {
+            _source.resume();
+        }
+
+        bool isPaused {
+            get { return _source.isPaused; }
+        }
-    public override void resume() {
-        _source.resume();
+        public override Future<E> asFuture<E>(E futureValue) => _source.asFuture<E>(futureValue);
-    bool isPaused {
-        get { return _source.isPaused; }
-    }
-    public override Future<E> asFuture<E>(E futureValue) => _source.asFuture<E>(futureValue);
-}
+    class CastStreamTransformer<SS, ST, TS, TT>
+        : StreamTransformerBase<TS, TT> where TT : class where ST : class {
+        public readonly StreamTransformer<SS, ST> _source;
+        public CastStreamTransformer(StreamTransformer<SS, ST> _source) {
+            this._source = _source;
+        }
-class CastStreamTransformer<SS, ST, TS, TT>
-    : StreamTransformerBase<TS, TT> where TT : class where ST : class {
-    public readonly StreamTransformer<SS, ST> _source;
+        public override StreamTransformer<RS, RT> cast<RS, RT>() =>
+            new CastStreamTransformer<SS, ST, RS, RT>(_source);
-    public CastStreamTransformer(StreamTransformer<SS, ST> _source) {
-        this._source = _source;
+        public override Stream<TT> bind(Stream<TS> stream) =>
+            _source.bind(stream.cast<SS>()).cast<TT>();
-
-    public override StreamTransformer<RS, RT> cast<RS, RT>() =>
-        new CastStreamTransformer<SS, ST, RS, RT>(_source);
-
-    public override Stream<TT> bind(Stream<TS> stream) =>
-        _source.bind(stream.cast<SS>()).cast<TT>();
 }

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

 using System.Collections.Generic;
 using Unity.UIWidgets.async;
 using Unity.UIWidgets.foundation;
-using Unity.UIWidgets.widgets;
+namespace Unity.UIWidgets.widgets {
+    public abstract class StreamBuilderBase<T, S> : StatefulWidget {
+        public StreamBuilderBase(Key key = null, Stream<T> stream = null) : base(key: key) {
+            this.stream = stream;
+        }
-public abstract class StreamBuilderBase<T, S> : StatefulWidget {
-    public StreamBuilderBase(Key key = null, Stream<T> stream = null) : base(key: key) {
-        this.stream = stream;
-    }
+        public readonly Stream<T> stream;
-    public readonly Stream<T> stream;
+        public abstract S initial();
-    public abstract S initial();
+        public virtual S afterConnected(S current) => current;
-    public virtual S afterConnected(S current) => current;
+        public abstract S afterData(S current, T data);
-    public abstract S afterData(S current, T data);
+        public virtual S afterError(S current, object error) => current;
-    public virtual S afterError(S current, object error) => current;
+        public virtual S afterDone(S current) => current;
-    public virtual S afterDone(S current) => current;
+        public virtual S afterDisconnected(S current) => current;
-    public virtual S afterDisconnected(S current) => current;
+        public abstract Widget build(BuildContext context, S currentSummary);
-    public abstract Widget build(BuildContext context, S currentSummary);
+        public override State createState() => new _StreamBuilderBaseState<T, S>();
+    }
-    public override State createState() => new _StreamBuilderBaseState<T, S>();
-}
+    class _StreamBuilderBaseState<T, S> : State<StreamBuilderBase<T, S>> {
+        StreamSubscription<T> _subscription;
+        S _summary;
-class _StreamBuilderBaseState<T, S> : State<StreamBuilderBase<T, S>> {
-    StreamSubscription<T> _subscription;
-    S _summary;
+        public override void initState() {
+            base.initState();
+            _summary = widget.initial();
+            _subscribe();
+        }
-    public override void initState() {
-        base.initState();
-        _summary = widget.initial();
-        _subscribe();
-    }
+        public override void didUpdateWidget(StatefulWidget statefulWidget) {
+            StreamBuilderBase<T, S> oldWidget = statefulWidget as StreamBuilderBase<T, S>;
+            if (oldWidget == null) {
+                return;
+            }
-    public override void didUpdateWidget(StatefulWidget statefulWidget) {
-        StreamBuilderBase<T, S> oldWidget = statefulWidget as StreamBuilderBase<T, S>;
-        if (oldWidget == null) {
-            return;
-        }
+            base.didUpdateWidget(statefulWidget);
+            if (oldWidget != null) {
+                if (oldWidget.stream != widget.stream) {
+                    if (_subscription != null) {
+                        _unsubscribe();
+                        _summary = widget.afterDisconnected(_summary);
+                    }
-        base.didUpdateWidget(statefulWidget);
-        if (oldWidget != null) {
-            if (oldWidget.stream != widget.stream) {
-                if (_subscription != null) {
-                    _unsubscribe();
-                    _summary = widget.afterDisconnected(_summary);
+                    _subscribe();
-
-                _subscribe();
-    }
-    public override Widget build(BuildContext context) => widget.build(context, _summary);
+        public override Widget build(BuildContext context) => widget.build(context, _summary);
-    public override void dispose() {
-        _unsubscribe();
-        base.dispose();
-    }
+        public override void dispose() {
+            _unsubscribe();
+            base.dispose();
+        }
-    void _subscribe() {
-        if (widget.stream != null) {
-            _subscription = widget.stream.listen(
-                (T data) => { setState(() => { _summary = widget.afterData(_summary, data); }); },
-                onError: (object error, string stackTrace) => { setState(() => { _summary = widget.afterError(_summary, error); }); },
-                onDone: () => { setState(() => { _summary = widget.afterDone(_summary); }); });
-            _summary = widget.afterConnected(_summary);
+        void _subscribe() {
+            if (widget.stream != null) {
+                _subscription = widget.stream.listen(
+                    (T data) => { setState(() => { _summary = widget.afterData(_summary, data); }); },
+                    onError: (object error, string stackTrace) => {
+                        setState(() => { _summary = widget.afterError(_summary, error); });
+                    },
+                    onDone: () => { setState(() => { _summary = widget.afterDone(_summary); }); });
+                _summary = widget.afterConnected(_summary);
+            }
-    }
-    void _unsubscribe() {
-        if (_subscription != null) {
-            _subscription.cancel();
-            _subscription = null;
+        void _unsubscribe() {
+            if (_subscription != null) {
+                _subscription.cancel();
+                _subscription = null;
+            }
-}
-public enum ConnectionState {
-    none,
+    public enum ConnectionState {
+        none,
-    waiting,
+        waiting,
-    active,
+        active,
-    done,
-}
+        done,
+    }
-public class AsyncSnapshot<T> : IEquatable<AsyncSnapshot<T>> {
-    AsyncSnapshot(ConnectionState connectionState, object data, object error) {
-        D.assert(connectionState != null);
-        D.assert(!(data != null && error != null));
-        this.connectionState = connectionState;
-        this.data = (T) data;
-        this.error = error;
-    }
+    public class AsyncSnapshot<T> : IEquatable<AsyncSnapshot<T>> {
+        AsyncSnapshot(ConnectionState connectionState, object data, object error) {
+            D.assert(connectionState != null);
+            D.assert(!(data != null && error != null));
+            this.connectionState = connectionState;
+            this.data = (T) data;
+            this.error = error;
+        }
-    public static AsyncSnapshot<object> nothing() {
-        return new AsyncSnapshot<object>(ConnectionState.none, null, null);
-    }
+        public static AsyncSnapshot<object> nothing() {
+            return new AsyncSnapshot<object>(ConnectionState.none, null, null);
+        }
-    public static AsyncSnapshot<T> withData(ConnectionState state, T data) {
-        return new AsyncSnapshot<T>(state, data, null);
-    }
+        public static AsyncSnapshot<T> withData(ConnectionState state, T data) {
+            return new AsyncSnapshot<T>(state, data, null);
+        }
-    public static AsyncSnapshot<T> withError(ConnectionState state, object error) {
-        return new AsyncSnapshot<T>(state, null, error);
-    }
+        public static AsyncSnapshot<T> withError(ConnectionState state, object error) {
+            return new AsyncSnapshot<T>(state, null, error);
+        }
-    public readonly ConnectionState connectionState;
+        public readonly ConnectionState connectionState;
-    public readonly T data;
+        public readonly T data;
-    public T requireData {
-        get {
-            if (hasData)
-                return data;
-            if (hasError)
-                //TODO: not sure if cast works
-                throw (Exception) error;
-            throw new Exception("Snapshot has neither data nor error");
+        public T requireData {
+            get {
+                if (hasData)
+                    return data;
+                if (hasError)
+                    //TODO: not sure if cast works
+                    throw (Exception) error;
+                throw new Exception("Snapshot has neither data nor error");
+            }
-    }
-    public readonly object error;
+        public readonly object error;
-    public AsyncSnapshot<T> inState(ConnectionState state) {
-        return new AsyncSnapshot<T>(state, data, error);
-    }
+        public AsyncSnapshot<T> inState(ConnectionState state) {
+            return new AsyncSnapshot<T>(state, data, error);
+        }
-    public bool hasData {
-        get => data != null;
-    }
-
-    public bool hasError {
-        get => error != null;
-    }
+        public bool hasData {
+            get => data != null;
+        }
-    public override string ToString() =>
-        $"{foundation_.objectRuntimeType(this, "AsyncSnapshot")}({connectionState}, {data}, {error})";
+        public bool hasError {
+            get => error != null;
+        }
-    public static bool operator ==(AsyncSnapshot<T> left, AsyncSnapshot<T> right) {
-        return Equals(left, right);
-    }
+        public override string ToString() =>
+            $"{foundation_.objectRuntimeType(this, "AsyncSnapshot")}({connectionState}, {data}, {error})";
-    public static bool operator !=(AsyncSnapshot<T> left, AsyncSnapshot<T> right) {
-        return !Equals(left, right);
-    }
-
-    public bool Equals(AsyncSnapshot<T> other) {
-        if (ReferenceEquals(null, other)) {
-            return false;
+        public static bool operator ==(AsyncSnapshot<T> left, AsyncSnapshot<T> right) {
+            return Equals(left, right);
-        if (ReferenceEquals(this, other)) {
-            return true;
+        public static bool operator !=(AsyncSnapshot<T> left, AsyncSnapshot<T> right) {
+            return !Equals(left, right);
-        return connectionState == other.connectionState && EqualityComparer<T>.Default.Equals(data, other.data) &&
-               Equals(error, other.error);
-    }
+        public bool Equals(AsyncSnapshot<T> other) {
+            if (ReferenceEquals(null, other)) {
+                return false;
+            }
-    public override bool Equals(object obj) {
-        if (ReferenceEquals(null, obj)) {
-            return false;
-        }
+            if (ReferenceEquals(this, other)) {
+                return true;
+            }
-        if (ReferenceEquals(this, obj)) {
-            return true;
+            return connectionState == other.connectionState && EqualityComparer<T>.Default.Equals(data, other.data) &&
+                   Equals(error, other.error);
-        if (obj.GetType() != GetType()) {
-            return false;
-        }
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) {
+                return false;
+            }
-        return Equals((AsyncSnapshot<T>) obj);
-    }
+            if (ReferenceEquals(this, obj)) {
+                return true;
+            }
-    public override int GetHashCode() {
-        unchecked {
-            var hashCode = (int) connectionState;
-            hashCode = (hashCode * 397) ^ EqualityComparer<T>.Default.GetHashCode(data);
-            hashCode = (hashCode * 397) ^ (error != null ? error.GetHashCode() : 0);
-            return hashCode;
+            if (obj.GetType() != GetType()) {
+                return false;
+            }
+
+            return Equals((AsyncSnapshot<T>) obj);
+        }
+
+        public override int GetHashCode() {
+            unchecked {
+                var hashCode = (int) connectionState;
+                hashCode = (hashCode * 397) ^ EqualityComparer<T>.Default.GetHashCode(data);
+                hashCode = (hashCode * 397) ^ (error != null ? error.GetHashCode() : 0);
+                return hashCode;
+            }
-}
-public static partial class _async {
-    public delegate Widget AsyncWidgetBuilder<T>(BuildContext context, AsyncSnapshot<T> snapshot);
-}
+    public static partial class _async {
+        public delegate Widget AsyncWidgetBuilder<T>(BuildContext context, AsyncSnapshot<T> snapshot);
+    }
-public class StreamBuilder<T> : StreamBuilderBase<T, AsyncSnapshot<T>> {
-    public StreamBuilder(
-        _async.AsyncWidgetBuilder<T> builder,
-        Key key = null,
-        T initialData = default,
-        Stream<T> stream = null
-    ) : base(key: key, stream: stream) {
-        D.assert(builder != null);
-        this.builder = builder;
-        this.initialData = initialData;
-    }
+    public class StreamBuilder<T> : StreamBuilderBase<T, AsyncSnapshot<T>> {
+        public StreamBuilder(
+            _async.AsyncWidgetBuilder<T> builder,
+            Key key = null,
+            T initialData = default,
+            Stream<T> stream = null
+        ) : base(key: key, stream: stream) {
+            D.assert(builder != null);
+            this.builder = builder;
+            this.initialData = initialData;
+        }
-    public readonly _async.AsyncWidgetBuilder<T> builder;
+        public readonly _async.AsyncWidgetBuilder<T> builder;
-    public readonly T initialData;
+        public readonly T initialData;
-    public override
-        AsyncSnapshot<T> initial() => global::AsyncSnapshot<T>.withData(ConnectionState.none, initialData);
+        public override
+            AsyncSnapshot<T> initial() => AsyncSnapshot<T>.withData(ConnectionState.none, initialData);
-    public override
-        AsyncSnapshot<T> afterConnected(AsyncSnapshot<T> current) => current.inState(ConnectionState.waiting);
+        public override
+            AsyncSnapshot<T> afterConnected(AsyncSnapshot<T> current) => current.inState(ConnectionState.waiting);
-    public override
-        AsyncSnapshot<T> afterData(AsyncSnapshot<T> current, T data) {
-        return global::AsyncSnapshot<T>.withData(ConnectionState.active, data);
-    }
+        public override
+            AsyncSnapshot<T> afterData(AsyncSnapshot<T> current, T data) {
+            return AsyncSnapshot<T>.withData(ConnectionState.active, data);
+        }
-    public override
-        AsyncSnapshot<T> afterError(AsyncSnapshot<T> current, object error) {
-        return AsyncSnapshot<T>.withError(ConnectionState.active, error);
-    }
+        public override
+            AsyncSnapshot<T> afterError(AsyncSnapshot<T> current, object error) {
+            return AsyncSnapshot<T>.withError(ConnectionState.active, error);
+        }
-    public override
-        AsyncSnapshot<T> afterDone(AsyncSnapshot<T> current) => current.inState(ConnectionState.done);
+        public override
+            AsyncSnapshot<T> afterDone(AsyncSnapshot<T> current) => current.inState(ConnectionState.done);
-    public override
-        AsyncSnapshot<T> afterDisconnected(AsyncSnapshot<T> current) => current.inState(ConnectionState.none);
+        public override
+            AsyncSnapshot<T> afterDisconnected(AsyncSnapshot<T> current) => current.inState(ConnectionState.none);
-    public override
-        Widget build(BuildContext context, AsyncSnapshot<T> currentSummary) => builder(context, currentSummary);
-}
-
-// TODO(ianh): remove unreachable code above once https://github.com/dart-lang/linter/issues/1141 is fixed
-class FutureBuilder<T> : StatefulWidget {
-    public FutureBuilder(
-        _async.AsyncWidgetBuilder<T> builder,
-        Key key = null,
-        Future<T> future = null,
-        T initialData = default
-    ) :
-        base(key: key) {
-        D.assert(builder != null);
-        this.builder = builder;
-        this.future = future;
-        this.initialData = initialData;
+        public override
+            Widget build(BuildContext context, AsyncSnapshot<T> currentSummary) => builder(context, currentSummary);
-    public readonly Future<T> future;
-
-    public readonly _async.AsyncWidgetBuilder<T> builder;
+// TODO(ianh): remove unreachable code above once https://github.com/dart-lang/linter/issues/1141 is fixed
+    class FutureBuilder<T> : StatefulWidget {
+        public FutureBuilder(
+            _async.AsyncWidgetBuilder<T> builder,
+            Key key = null,
+            Future<T> future = null,
+            T initialData = default
+        ) :
+            base(key: key) {
+            D.assert(builder != null);
+            this.builder = builder;
+            this.future = future;
+            this.initialData = initialData;
+        }
-    public readonly T initialData;
+        public readonly Future<T> future;
-    public override
-        State createState() => new _FutureBuilderState<T>();
-}
+        public readonly _async.AsyncWidgetBuilder<T> builder;
-class _FutureBuilderState<T> : State<FutureBuilder<T>> {
-    object _activeCallbackIdentity;
-    AsyncSnapshot<T> _snapshot;
+        public readonly T initialData;
-    public override
-        void initState() {
-        base.initState();
-        _snapshot = AsyncSnapshot<T>.withData(ConnectionState.none, widget.initialData);
-        _subscribe();
+        public override
+            State createState() => new _FutureBuilderState<T>();
-    public override
-        void didUpdateWidget(StatefulWidget statefulWidget) {
-        var oldWidget = statefulWidget as FutureBuilder<T>;
-        if (oldWidget == null) {
-            return;
+    class _FutureBuilderState<T> : State<FutureBuilder<T>> {
+        object _activeCallbackIdentity;
+        AsyncSnapshot<T> _snapshot;
+
+        public override
+            void initState() {
+            base.initState();
+            _snapshot = AsyncSnapshot<T>.withData(ConnectionState.none, widget.initialData);
+            _subscribe();
-        base.didUpdateWidget(oldWidget);
-        if (oldWidget.future != widget.future) {
-            if (_activeCallbackIdentity != null) {
-                _unsubscribe();
-                _snapshot = _snapshot.inState(ConnectionState.none);
+        public override
+            void didUpdateWidget(StatefulWidget statefulWidget) {
+            var oldWidget = statefulWidget as FutureBuilder<T>;
+            if (oldWidget == null) {
+                return;
-            _subscribe();
+            base.didUpdateWidget(oldWidget);
+            if (oldWidget.future != widget.future) {
+                if (_activeCallbackIdentity != null) {
+                    _unsubscribe();
+                    _snapshot = _snapshot.inState(ConnectionState.none);
+                }
+
+                _subscribe();
+            }
-    }
-    public override
-        Widget build(BuildContext context) => widget.builder(context, _snapshot);
+        public override
+            Widget build(BuildContext context) => widget.builder(context, _snapshot);
-    public override
-        void dispose() {
-        _unsubscribe();
-        base.dispose();
-    }
+        public override
+            void dispose() {
+            _unsubscribe();
+            base.dispose();
+        }
-    void _subscribe() {
-        if (widget.future != null) {
-            object callbackIdentity = new object();
-            _activeCallbackIdentity = callbackIdentity;
-            widget.future.then((object dataIn) => {
-                var data = (T) dataIn;
-                if (_activeCallbackIdentity == callbackIdentity) {
-                    setState(() => { _snapshot = AsyncSnapshot<T>.withData(ConnectionState.done, data); });
-                }
-            }, onError: (Exception error) => {
-                if (_activeCallbackIdentity == callbackIdentity) {
-                    setState(() => { _snapshot = AsyncSnapshot<T>.withError(ConnectionState.done, error); });
-                }
+        void _subscribe() {
+            if (widget.future != null) {
+                object callbackIdentity = new object();
+                _activeCallbackIdentity = callbackIdentity;
+                widget.future.then((object dataIn) => {
+                    var data = (T) dataIn;
+                    if (_activeCallbackIdentity == callbackIdentity) {
+                        setState(() => { _snapshot = AsyncSnapshot<T>.withData(ConnectionState.done, data); });
+                    }
+                }, onError: (Exception error) => {
+                    if (_activeCallbackIdentity == callbackIdentity) {
+                        setState(() => { _snapshot = AsyncSnapshot<T>.withError(ConnectionState.done, error); });
+                    }
-                return FutureOr.nil;
-            });
-            _snapshot = _snapshot.inState(ConnectionState.waiting);
+                    return FutureOr.nil;
+                });
+                _snapshot = _snapshot.inState(ConnectionState.waiting);
+            }
-    }
-    void _unsubscribe() {
-        _activeCallbackIdentity = null;
+        void _unsubscribe() {
+            _activeCallbackIdentity = null;
+        }
     }
 }