@SuppressWarnings("WeakerAccess")
    public void stopAsync() {
        log.debug("Shutting down embedded Kafka broker at {} (with ZK ensemble at {}) ...",
                  brokerList(), zookeeperConnect());
        kafka.shutdown();
    }
The ZooKeeper connection string aka `zookeeper.connect`.
streams/src/test/java/org/apache/kafka/streams/integration/utils/KafkaEmbedded.java