anchor.diff:    @observable bool isStackingHistory = false;
   
     Timer zippedJsonUpdater;
  +  Function afterRendered;
   
     PixelCanvasElement get canvas => shadowRoot.querySelector('pixel-canvas');
     AnsiColorPaletteElement get _palette =>
  
positive.code:   @override
    attached() {
      super.attached();
      _initController();
      _asyncUpdateContainterSize();
  
      _startUrlFragmentObsevation();
  
      async((_) { _updateZipped();});
      _initLocalStorageProps();
    }
  
negative.code: 
      canvas.onPixelColorChange.listen((_) {
        _delayUpdateZipped();
      });
      canvas.onAfterRendering.listen((_) {
        if (afterRendered == null) return;
        afterRendered();
      });
    }
  
  