anchor.diff:      });
     }
   
  -  bool get _isComposing => _currentMessage == null || _currentMessage.length == null > 0;
  +  bool get _isComposing => _currentMessage.length > 0;
   
     Widget _buildTextComposer() {
       return new Column(
  
positive.code:       return null;
      Map<String, String> message = _messages[index];
      return new Container(
        margin: const EdgeDims.all(3.0),
        child: new Center(
          child: new Text("${message['name']}: ${message['text']}")
  
negative.code:       'text': text,
      };
      _firebase.push().set(message);
    }
  
    Widget _buildMessage(int index) {
  