anchor.diff:          super(key: key);
   
     @override
  -  _RTCVideoViewState createState() => new _RTCVideoViewState();
  +  _RTCVideoViewState createState() => _RTCVideoViewState();
   }
   
   class _RTCVideoViewState extends State<RTCVideoView> {
  
positive.code:         height: constraints.maxHeight,
          child: FittedBox(
              fit: widget.objectFit == RTCVideoViewObjectFit.RTCVideoViewObjectFitContain ? BoxFit.contain : BoxFit.cover,
              child: new Center(
                  child: new SizedBox(
                      width: constraints.maxHeight * _aspectRatio,
                      height: constraints.maxHeight,
                      child: new Transform(
                          transform: Matrix4.identity()
                            ..rotateY(widget.mirror ? -pi : 0.0),
                          alignment: FractionalOffset.center,
                          child:
                              new Texture(textureId: widget._renderer._textureId))))));
    }
  
    @override
  
negative.code:     bool renderVideo =
          (widget._renderer._textureId != null && widget._renderer._srcObject != null);
  
      return LayoutBuilder(
          builder: (BuildContext context, BoxConstraints constraints) {
        return Center(
            child: renderVideo ? _buildVideoView(constraints) : Container());
      });
    }
  }
  