anchor.diff:  
     void _createStream() {
       _stream = widget.store.onChange
  +        .where(_stateChanged)
           .where(_ignoreChange)
           .map(_mapConverter)
           // Don't use `Stream.distinct` because it cannot capture the initial
  
positive.code:   Stream<ViewModel> _stream;
    ViewModel _latestValue;
    ConverterError _latestError;
  
    @override
    void initState() {
  
negative.code: 
    bool _ignoreChange(S state) {
      if (widget.ignoreChange != null) {
        return !widget.ignoreChange(widget.store.state);
      }
  
      return true;
  