What's the difference between a retriable and a non-retriable producer error in Kafka, and why does that distinction matter?

A retriable error (like a temporary leader-election in progress) is transient and safe to automatically retry — the Kafka producer client can handle this internally with configured retries. A non-retriable error (like a message exceeding the configured max size) will fail identically no matter how many times you retry, so blindly retrying it just wastes time and delays surfacing a real problem that needs code/config changes.