public KafkaSource zkConnect(String zkConnect) {
		Assert.hasText(zkConnect, "zkConnect must not be empty nor null");
		this.zkConnect = zkConnect;
		return this;
	}
set the zkConnect for the kafka source

@param zkConnect the zookeeper connection string to be used
@return instance of the kafka source
spring-xd-test-fixtures/src/main/java/org/springframework/xd/test/fixtures/KafkaSource.java