My experience is building streaming systems using “exactly-once delivery” primitives is much more awkward than designing your system around at least once primit

My experience is building streaming systems using “exactly-once delivery” primitives is much more awkward than designing your system around at least once primitives and explicitly de-duplicating using last-write wins. For one thing, LWW gives you an obvious recovery strategy if you have outages of the primitive your system is built on: a lot of the exactly once modes for tools make failure recovery harder than necessary