title: In Apache Kafka, how can I have conditional message publication in order to support Optimistic Concurrency
body: <p>I want to use Apache Kafka to power an event-sourced persistence.</p>
  
  <p>I know that other event-based persistence support Optimistic Concurrency, such as described <a href="https://eventstore.org/docs/dotnet-api/3.0.1/optimistic-concurrency-and-idempotence/" rel="nofollow noreferrer">in Event Store documentation</a>, however, <a href="https://issues.apache.org/jira/browse/KAFKA-2260" rel="nofollow noreferrer">the following - still unresolved, low-priority - ticket</a> seems to indicate it is not a possibility at this time.</p>
  
  <p>Anyone with an idea ?</p>