Duplicate row insertion on retry in Pulsar IO JDBC sink
The goal is to achieve exactly‑once write semantics when a Pulsar IO JDBC sink retries a message after a transient failure. Transactional producers bypass broker‑side deduplication, so relying on deduplicationEnabled=true does not prevent duplicate inserts on retry. The sink receives the same message again and, if the JDBC operation is a plain INSERT, each r