@Override
        public void handleStateChanged(final KeeperState state) throws Exception {
            // do nothing, since zkclient will do reconnect for us.

        }
When we get a SessionExpired event, we lost all ephemeral nodes
and zkclient has reestablished a connection for us. We need to
release the ownership of the current consumer and re-register
this consumer in the consumer registry and trigger a rebalance.
metamorphosis-client/src/main/java/com/taobao/metamorphosis/client/consumer/ConsumerZooKeeper.java