581 / 1048 · Module 12 — Idempotency and Duplicate Prevention← prev⊞ allnext →12.52Test 5 — concurrent duplicate messagesPublish: EVT-999 to multiple workers/concurrent execution. Verify: one business effect ← Previous12.51 Test 4 — same idempotency key, different payloadNext →12.53 Test 6 — stale version