@Override
    public void serverStopping(Server server) {
        if (closeClientOnStop) {
            client.close();
        }
    }
Returns a {@link ZooKeeperUpdatingListenerBuilder} with a ZooKeeper connection string and a znode path.

@param zkConnectionStr the ZooKeeper connection string
@param znodePath the ZooKeeper node to register
@param spec the {@link ZooKeeperRegistrationSpec} to encode and register the {@link Server}
zookeeper3/src/main/java/com/linecorp/armeria/server/zookeeper/ZooKeeperUpdatingListener.java