anchor.diff:  
     /// Subscribes to this object.
     ///
  -  /// The [listener] callback will be called immediatly on addition and
  +  /// The [listener] callback will be called immediately on addition and
     /// synchronously whenever [state] changes.
     ///
     /// To remove this [listener], call the function returned by [addListener]:
  
positive.code: 
    bool _mounted = true;
  
    /// Wether [dispose] was called or not.
    bool get mounted => _mounted;
  
    bool _debugCanAddListeners = true;
  
negative.code:     return _state;
    }
  
    /// A development-only way to access [state] outside of [StateNotifier].
    ///
    /// The only difference with [state] is that [debugState] is not "protected".\
    /// Will not work in release mode.
  