anchor.diff:    void initState() {
       _firebase = new Firebase("https://firechat-flutter.firebaseio.com/");
       _user = "Guest${new math.Random().nextInt(1000)}";
  +    _currentMessage = '';
       _firebase.onChildAdded.listen((Event event) {
         Map<String, String> message = event.snapshot.val();
         setState(() => _messages.add(message));
  
positive.code:     });
    }
  
    bool get _isComposing => _currentMessage == null || _currentMessage.length == null > 0;
  
    Widget _buildTextComposer() {
      return new Column(
  
negative.code:       'text': text,
      };
      _firebase.push().set(message);
    }
  
    Widget _buildMessage(int index) {
  