anchor.diff:     * * _name: the state's name
      * * nextState: next state's name(optional)
      * */
  -  State(this._name, [String nextState = null]): _nextStateName = nextState {
  +  State(this._name, [String nextState = null]): nextState = nextState {
       _controller = new StreamController<String>(onListen: _onListen, onPause:
           _onPause, onResume: _onResume, onCancel: _onCancel);
     }
  
positive.code:   String get name => _name;
  
    /**
     * Gets the next state's name.
     * 
     * **Important:** You can controll where you want to go with nextState method.
     * */
    String get nextState => _nextStateName;
  
    set nextState(state) => _nextStateName = state;
  
    /**
     * You can send message to the StateManager.
     * */
    void addMessage(message) {
  
negative.code: 
    StreamController<String> _controller;
    String _name;
    /**
     * The next state's name.
     * 
     * **Important:** You can controll where you want to go with this member.
     */
    String nextState;
    /**
     * Acces to the main game object.
     * */
  