minor fix

com.unity.uiwidgets/Runtime/rendering/object.mixin.gen.cs

             get { return _childCount; }
         }
 
-        public bool debugValidateChild(RenderObject child) {
+        public override bool debugValidateChild(RenderObject child) {
             D.assert(() => {
                 if (!(child is ChildType)) {
                     throw new UIWidgetsError(

com.unity.uiwidgets/Runtime/rendering/object.mixin.njk

 {{ ContainerParentDataMixin('SliverLogicalParentData') }}
 
 
-{% macro ContainerRenderObjectMixin(with) %}
+{% macro ContainerRenderObjectMixin(override, with) %}
     public abstract class ContainerRenderObjectMixin{{with}}<ChildType, ParentDataType> : {{with}}, ContainerRenderObjectMixin
         where ChildType : RenderObject
         where ParentDataType : ParentData, ContainerParentDataMixin<ChildType> {
             get { return _childCount; }
         }
 
-        public bool debugValidateChild(RenderObject child) {
+        public {{override}}bool debugValidateChild(RenderObject child) {
             D.assert(() => {
                 if (!(child is ChildType)) {
                     throw new UIWidgetsError(
     }
 {% endmacro %}
 
-{{ ContainerRenderObjectMixin('RenderBox') }}
+{{ ContainerRenderObjectMixin('', 'RenderBox') }}
-{{ ContainerRenderObjectMixin('RenderSliver') }}
+{{ ContainerRenderObjectMixin('', 'RenderSliver') }}
-{{ ContainerRenderObjectMixin('RenderProxyBoxMixinRenderObjectWithChildMixinRenderBoxRenderStack') }}
+{{ ContainerRenderObjectMixin('override ', 'RenderProxyBoxMixinRenderObjectWithChildMixinRenderBoxRenderStack') }}
 
 {% macro RenderConstrainedLayoutBuilderMixin(abstract, with, constraint) %}
 public {{abstract}} class RenderConstrainedLayoutBuilderMixin{{with}}<ConstraintType, ChildType> : RenderObjectWithChildMixin{{with}}<ChildType>,

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

         }
 
 #pragma warning disable CS0108
-        public RenderObjectWidget widget {
+        public new RenderObjectWidget widget {
             get { return (RenderObjectWidget) base.widget; }
         }
 #pragma warning restore CS0108

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

             widget.notifier?.addListener(_handleUpdate);
         }
 
+#pragma warning disable CS0108
+#pragma warning restore CS0108
         
         //In flutter this variable is named as _dirty and hides the property of its parent with the name variable name
         //We give it a new name, i.e., _notifier_dirty in UIWidgets so that the code looks more clear