public void finishSession() {
    if (mSession != null) {
      mSession.disconnect();
      mSession = null;
    }

    mInstance = null;
  }
 public void disconnect() {
   if (videoInSubscriber != null) {
     getSession().unsubscribe(videoInSubscriber);
   }
   if (videoOutPublisher != null) {
     getSession().unpublish(videoOutPublisher);
   }
   Session session = getSession();
   session.disconnect();
 }
 @Override
 public void onDestroy() {
   super.onDestroy();
   if (mStreams != null) {
     mStreams.clear();
   }
   this.mSubscriber = null;
   if (mSession != null) {
     mSession.disconnect();
   }
   if (videoFlyHead != null) windowManager.removeView(videoFlyHead);
 }