A message with this MessageID is already stored (03 §2.1, F10 — MessageID is globally unique). Same topic and same
canonical envelope → Duplicate; anything else → MessageIDConflict. existing is undefined when the conflicting row
was not visible to the follow-up read (purged in between): the caller retries.
A message with this MessageID is already stored (03 §2.1, F10 — MessageID is globally unique). Same topic and same canonical envelope → Duplicate; anything else → MessageIDConflict.
existingis undefined when the conflicting row was not visible to the follow-up read (purged in between): the caller retries.