code: public void dismiss() {
          for (int i = 0; i < restartables.size(); i++)
              dismiss(restartables.keyAt(i));
      }
  
      private Restartable restartable(int id) {
          if (restartables.get(id) == null)
              restartables.put(id, new Restartable(out.child(Integer.toString(id))));
          return restartables.get(id);
      }
  }
docs: Unsubscribes and dismisses all controlled observables.