عرض عملي: ماذا تفعل إعادة الموازنة (rebalance) بالرسائل قيد المعالجة

خطوة بخطوة

1. Start two inventory consumers; note partition assignments.
2. Make the handler slow (5 s) and record each processed eventId.
3. Kill one consumer mid-processing; watch partitions reassign.
4. The surviving consumer re-reads from the last committed offset; show a message processed twice.
5. Planned mistake: enable auto-commit before processing and show a message lost on a crash. Fix by committing after processing.
6. Add an idempotency check on eventId and replay; the duplicate no longer has an effect.