anchor.diff:        physicalHeight,
         sceneToken.value
       );
  +    Timeline.finishSync();
     }
   
     @override
  
positive.code: 
    @override
    void addToScene(ui.SceneBuilder builder, Offset layerOffset) {
      builder.addChildScene(
        offset + layerOffset,
        devicePixelRatio,
  
negative.code: 
    @override
    void addToScene(ui.SceneBuilder builder, Offset layerOffset) {
      Timeline.startSync('ClipRectLayer::addToScene');
      builder.pushClipRect(clipRect.shift(layerOffset));
      addChildrenToScene(builder, layerOffset);
      builder.pop();
      Timeline.finishSync();
    }
  
    @override
  