listen(event, listener) {
    this
      .connectIO()
      .on(event, listener);
  }
/**
   * Add a listener to an event
   *
   * @param event
   * @param listener
   */
Add a listener to an event
@param event
@param listener
Add a listener to an event @param event @param listener
listen(event, listener) {
    this
      .connectIO()
      .on(event, listener);
  }
listen ( event , listener ) { this . connectIO ( ) . on ( event , listener ) ; }
Add a listener to an event
 @param event
 @param listener
Add a listener to an event @param event @param listener