Hi, As outlined in KIP-799: Align behaviour for producer callbacks with documented behaviour <https://cwiki.apache.org/confluence/display/KAFKA/KIP-799%3A+Align+behaviour+for+producer+callbacks+with+documented+behaviour>, there is an inconsistency between the documented behaviour and implementation of producer callbacks for the Kafka client. The KIP proposes breaking changes to the implementation of the Kafka producer client to align the implementation with the documented behaviour, and includes a link to a PR containing a tested implementation of the changes being recommended.
There is a need to take action here as a breaking change was previously introduced accidentally, and the documentation was later updated to try to reflect those breaking changes. I believe the main discussion here is around the most appropriate behaviour for callbacks, which will inform whether the implementation, documentation or a combination of both should be updated. Right now, the documented behaviour aligns closely with the implementation of ProducerInterceptors, and as a result I would favor keeping the documented behaviour and updating the implementation to match, as that would provide greater consistency between Callbacks and Interceptors implementations for producers. Regards, Séamus.
