code: public void connectionDidLeave(final RespokeConnection connection) {
          members.remove(connection);
  
          new Handler(Looper.getMainLooper()).post(new Runnable() {
              @Override
              public void run() {
                  Listener listener = listenerReference.get();
                  if (null != listener) {
                      listener.onLeave(connection, RespokeGroup.this);
                  }
              }
          });
      }
docs: Notify the group that a connection has left. This is used internally to the SDK and should not be called directly by your client application.
  
  @param connection The connection that has left the group