docs: public void connect(String hosts) throws IOException, InterruptedException {
          internalHost = hosts;
          zk = new ZooKeeper(internalHost, SESSION_TIMEOUT, this);
  
          // 连接有超时哦
          connectedSignal.await(CONNECT_TIMEOUT, TimeUnit.MILLISECONDS);
  
          LOGGER.info("zookeeper: " + hosts + " , connected.");
      }