code: public void standaloneLogoff ()
      {
          notifyObservers(new ObserverOps.Session(this) {
              @Override protected void notify (SessionObserver obs) {
                  obs.clientDidLogoff(_client);
              }
          });
          cleanup(null); // this will set _standalone to false
      }
docs: For standalone mode, this notifies observers that the client has logged off and cleans up.