Also (in case this isn't obvious) I'm 100% a fan of the decision to _not_ tightly couple to the kafka wire protocol. Kafka's apis are full of landmines and gotchas, and you can do much better from a UX perspective if you're not married to their quirky semantics.

I had heard people talk about the operation pain involved in keeping Kafka alive (which is a thing for sure), but what I was surprised by was how many things behaved in a slightly unobvious manner that wasn't loudly-documented (e.g. if you're using transactions for RWP loops the default rebalance protocol is unsound and transaction markers take up an index in the log so you no longer have contiguous indices in your message stream etc).