public static ZooKeeperEndpointGroup of(String zkConnectionStr, String znodePath,
                                            ZooKeeperDiscoverySpec spec) {
        return builder(zkConnectionStr, znodePath, spec).build();
    }
Returns a new {@link ZooKeeperEndpointGroup} that retrieves the {@link Endpoint} list from
the ZNode at the specified connection string and path. A new ZooKeeper client will be created internally.
The ZooKeeper client will be destroyed when the returned {@link ZooKeeperEndpointGroup} is closed.

@param zkConnectionStr the ZooKeeper connection string
@param znodePath the ZooKeeper node to register
@param spec the {@link ZooKeeperDiscoverySpec} to find and decode the registered instances
zookeeper3/src/main/java/com/linecorp/armeria/client/zookeeper/ZooKeeperEndpointGroup.java