docs: public void sendUpdateNotificationAsyncronously(final String hub, final String topic, final AsyncNotificationCallback callback) {
          final Runnable r = new Runnable() {
              @Override
              public void run() {
                  try {
                      sendUpdateNotification(hub, topic);
                      callback.onSuccess();
                  } catch (final Throwable t) {
                      callback.onFailure(t);
                  }
              }
          };
  
          if (executor != null) {
              executor.execute(r);
          } else {
              new Thread(r).start();
          }
      }