[boredandroid]

Yes the idempotence part of this feature set is very similar to TCP (the transactional consumption and updates obviously aren't). But this isn't a reimplementation at all. TCP provides deduplication within the context of a connection tied to a process. If that connection is lost or the process dies then duplicates may occur. The feature in Kafka is much stronger as the "connection" is persistent and replicated with the log so effectively the "connection" fails over if the server dies.