title: CONNECTION_LOSS error in Zookeeper
body: <p>We have a consumer (using the kafka-node library) which consumes messages from a topic and then throws the following error when the offset is commited and the consumer is closed.</p>
  
  <pre><code>kafka-node:HighLevelConsumer HighLevelConsumer healthcheck_0d6af285-d35e-4edf-9d90-c5cdd7c37666 is attempting to rebalance +88ms
  kafka-node:HighLevelConsumer HighLevelConsumer healthcheck_0d6af285-d35e-4edf-9d90-c5cdd7c37666 stopping data read during rebalance +1ms
  kafka-node:HighLevelConsumer HighLevelConsumer healthcheck_0d6af285-d35e-4edf-9d90-c5cdd7c37666 assembling data for rebalance +0ms
  kafka-node:zookeeper Exception: CONNECTION_LOSS[-4]
  </code></pre>
  
  <p>Has anyone seen this before and why a "connection loss" would be reported.  The ZK server was up and running all the time.</p>
  
  <p>Thanks for any help anyone can offer</p>