public ZooKeeperUpdatingListener build() {
        final CuratorFramework client = buildCuratorFramework();
        final boolean internalClient = !isUserSpecifiedCuratorFramework();

        return new ZooKeeperUpdatingListener(client, znodePath(), spec, internalClient);
    }
Returns a newly-created {@link ZooKeeperUpdatingListener} instance that registers the server to
ZooKeeper when the server starts.
zookeeper3/src/main/java/com/linecorp/armeria/server/zookeeper/ZooKeeperUpdatingListenerBuilder.java