public void StartWatchingTopicEvents()
{
var topicEventListener = new ZkTopicEventListener(this);
ZkUtils.MakeSurePersistentPathExists(zkClient, ZkUtils.BrokerTopicsPath);
this.zkClient.SubscribeStateChanges(new ZkSessionExpireListener(this, topicEventListener));
var topics = this.zkClient.SubscribeChildChanges(ZkUtils.BrokerTopicsPath, topicEventListener);
// call to bootstrap topic list
topicEventListener.HandleChildChange(ZkUtils.BrokerTopicsPath, topics);
}