anchor.diff:                 
     }
     
  -  _onPause(){
  +  void _onPause(){
   	  print("Pause");
     }
     
  -  _onResume(){
  +  void _onResume(){
   	  print("Resume");
     }
     
  -  _onCancel(){
  +  void _onCancel(){
   	  print("Deconstructing");
     }
     
  
positive.code: import 'dart:async';
  
  abstract class State extends Stream<String> {
    
    StreamController _controller;
    String _nextState;
    
    State([String nextState = null]): _nextState = nextState {        
      _controller = new StreamController<String>(
      onListen: _onListen,
      onPause: _onPause,
      onResume: _onResume,
      onCancel: _onCancel);
    }
    
    StreamSubscription<String> listen(void onData(String line),
  
negative.code:                                      cancelOnError: cancelOnError);
    }
    
    void _onListen(){
  	  print("Constructing");
      preload();
      create();
  