anchor.diff:  
     @override
     void addToScene(ui.SceneBuilder builder, Offset layerOffset) {
  +    Timeline.startSync('PictureLayer::addToScene');
       builder.addPicture(layerOffset, picture);
  +    Timeline.finishSync();
     }
   }
   
  
positive.code: 
    @override
    void addToScene(ui.SceneBuilder builder, Offset layerOffset) {
      addChildrenToScene(builder, layerOffset);
    }
  
    /// Uploads all of this layer's children to the engine
  
negative.code: 
    @override
    void addToScene(ui.SceneBuilder builder, Offset layerOffset) {
      Timeline.startSync('ChildSceneLayer::addToScene');
      builder.addChildScene(
        offset + layerOffset,
        devicePixelRatio,
  