docs: public void close() throws ZkInterruptedException {
          if (_connection == null) {
              return;
          }
          LOG.debug("Closing ZkClient...");
          getEventLock().lock();
          try {
              setShutdownTrigger(true);
              _eventThread.interrupt();
              _eventThread.join(2000);
              _connection.close();
              _connection = null;
          } catch (InterruptedException e) {
              throw new ZkInterruptedException(e);
          } finally {
              getEventLock().unlock();
          }
          LOG.debug("Closing ZkClient...done");
      }