code: @Override
      public void close()
      {
          if ( treeState.compareAndSet(TreeState.STARTED, TreeState.CLOSED) )
          {
              client.getConnectionStateListenable().removeListener(connectionStateListener);
              listeners.clear();
              executorService.shutdown();
              try
              {
                  root.wasDeleted();
              }
              catch ( Exception e )
              {
                  ThreadUtils.checkInterrupted(e);
                  handleException(e);
              }
          }
      }
docs: Close/end the cache.