If it’s a retry of the same request it should have the same key. If it’s not a retry, a different one. I don’t see the issue.
replyIf the client sends the same key but a different payload that’s a 400 or 409 in my eyes.
It shouldn't, an error would be the right response.
reply1) Fresh UUID
reply2) Client's choice
now you are moving the core question to where the fresh UUID is calculated. a UUID is calculated or reused based on a process-defined decision.
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