anchor.diff:    void pause() {
       if (!_stop) {
         _pause = true;
  -    }
  +      _pauseStreamController.add(true);
  +    }
  +  }
  +
  +  Stream<bool> onPause() {
  +    return _pauseStreamController.stream;
     }
   
     bool get paused => _pause;
  
positive.code:         ctx = webgl
              ? (querySelector(canvasSelector) as CanvasElement).getContext3d()
              : (querySelector(canvasSelector) as CanvasElement).context2D
              as CanvasRenderingContext,
          _width = width,
          _height = height {
      canvas.width = width;
  
negative.code:   static const int rendering = 0;
    static const int physics = 1;
  
    final StreamController<bool> _pauseStreamController =
        new StreamController<bool>();
    final CanvasElement canvas;
    final CanvasRenderingContext ctx;
    final GameHelper helper;
  