title: Kafka connect FileStreamSink not exactly once
body: <p>I was thinking of using FileStreamSink Kafka Connect connector for some storage job, but from what I understand, it's not possible to have exactly once semantics when using this file connector ( I can write a record to the file and then crash before committing to Kafka).
  Before going to another kind of solution ( s3 sink connector offer EOS for instance) , I just want to make sure I'm right and FileStreamSink does not offer EOS.</p>
  
  <p>Someone can confirm?</p>