anchor.diff:     * An optional callback can be provided to be called when 
      * the connection to the mqtt broker has been lost
     */
  -  Future<int> connect([onConnectionLostCallback]) {
  +  Future<int> connect([onConnectionLostCallback, String uName, String uPassword]) {
       _connack = new Completer();
  +
  +    userName = uName != null ? uName : userName;
  +    userPassword = uPassword != null ? uPassword : userPassword;
       
       if (onConnectionLostCallback != null) onConnectionLost = onConnectionLostCallback;
       
  
positive.code:   /**
     * MqttClient constructor
     */
    MqttClient(E mqttConnection, {String clientID: '', num qos: 0x0, bool cleanSession:true} )
                : _mqttConnection = mqttConnection, _clientID = clientID, _qos = qos, _cleanSession = cleanSession, debugMessage = false, _will = null;  
    
    /**
  
negative.code:   var onSubscribeData = null;
    var onConnectionLost = null;
    Map<int, Completer>  _messagesToCompleteMap;
  
    String userName;
    String userPassword;
    
    var _liveTimer;
  
  