@Override
	public void afterPropertiesSet() throws Exception {
		zkConnection.addListener(connectionListener);
		if (zkConnection.isConnected()) {
			// already connected, invoke the callback directly
			connectionListener.onConnect(zkConnection.getClient());
		}
	}
The key used in serialized properties to hold the parsed module definitions that make up a stream.
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/stream/zookeeper/ZooKeeperStreamDefinitionRepository.java