docs: private void removeConnectionCallbacks() {
          connection.removeSyncStanzaListener(messageListener);
          connection.removeSyncStanzaListener(presenceListener);
          connection.removeSyncStanzaListener(subjectListener);
          connection.removeSyncStanzaListener(declinesListener);
          connection.removeStanzaInterceptor(presenceInterceptor);
          if (messageCollector != null) {
              messageCollector.cancel();
              messageCollector = null;
          }
      }