anchor.diff:  import 'dart:ui';
  +import 'package:collection/collection.dart' as collection;
   
   import 'package:flame/components.dart';
   import 'package:pinball_flame/src/canvas/canvas_wrapper.dart';
  
positive.code:   /// before the second one.
    /// {@endtemplate}
    void render() => _zBuffer
      ..sort((a, b) => a.zIndex.compareTo(b.zIndex))
      ..whereType<Component>().forEach(_render)
      ..clear();
  
    void _render(Component component) => component.renderTree(canvas);
  
negative.code:   final List<ZIndex> _zBuffer = [];
  
    /// Postpones the rendering of [ZIndex] component and its children.
    void buffer(ZIndex component) {
      final lowerBound = collection.lowerBound<ZIndex>(
        _zBuffer,
        component,
        compare: (a, b) => a.zIndex.compareTo(b.zIndex),
      );
      _zBuffer.insert(lowerBound, component);
    }
  
    /// Renders all [ZIndex] components and their children.
    ///
  