title: Kafka behaviour if consumer fail
body: <p>I've looked up throught a lot of different articles about Apache Kafka transactions, recovery and exactly-once new features. Still don't understand an issue with consumer recovery.  How to be sure that every message from queue will be processed even if one of consumers dies?</p>
  
  <p>Let's say we have a topic partition assigned to consumer. Consumer polls a message and started to work on it. And shutted down due to power failure without commit. What will happens? Will any other consumer from the same group repoll this message?</p>