Whenever a session is expired by ZooKeeper I see the following messages
(one per consumer I think) in the ZooKeeper log:

2014-03-25 00:05:12,953 - INFO  [ProcessThread:-1:PrepRequestProcessor@419]
- Got user-level KeeperException when processing
sessionid:0x344f675fcee0164 type:create cxid:0x7566 zxid:0xfffffffffffffffe
txntype:unknown reqpath:n/a Error
Path:/consumers/optimizer-group/owners/optimizer-default-topic/724
Error:KeeperErrorCode = NodeExists for
/consumers/optimizer-group/owners/optimizer-default-topic/724

Is this normal? Something the Kafka consumer recovers from?