title: How to get notified about expired kafka events
body: <p>Is there any mechanism to get notified (by a specific logfile entry or similar) in case an event within a kafka topic is expired due to retention policies? (I know this should avoided by design, but still).</p>
  <p>I know about consumer lag monitoring tools for monitoring offset discrepancies between a published event and related consumer groups but they provide afaik only numbers (the offset difference).</p>
  <p>In another simple words: <strong>How can we find out if kafka events were never consumed and therefore expired?</strong></p>