anchor.diff:  
     Future forEach(void action(T element)) => new _ReactableAsStream(this).forEach(action);
   
  -  Reactable<T> handleError(onError, {bool test(error)}) => new _ReactableAsStream(this).handleError(onError, test: test);
  +  Reactable<T> handleError(onError, {bool test(error)}) => new EventStream(
  +      new _ReactableAsStream(this).handleError(onError, test: test));
   
     Future<dynamic> lastWhere(bool test(T element), {Object defaultValue()}) =>
         new _ReactableAsStream(this).lastWhere(test, defaultValue: defaultValue);
  
positive.code:   /// [Stream.listen] method.
    StreamSubscription<T> listen(void onData(T event), {Function onError, void onDone(), bool cancelOnError});
  
    Reactable map(convert(T event)) => new _ReactableAsStream(this).map(convert);
  
    Future<T> reduce(T combine(T previous, T element)) => new _ReactableAsStream(this).reduce(combine);
  
  
negative.code:   /// Errors will always be forwarded regardless of the value of [toggle].
    Reactable<T> when(Reactable<bool> toggle) => new _WhenReactable(this, toggle);
  
    Reactable<T> where(bool test(T event)) => new EventStream(new _ReactableAsStream(this).where(test));
  }