KIP-547 — Extend ConsumerInterceptor to allow modification of Consumer Commits

Discussion Consumer

Extends `ConsumerInterceptor` with an `onCommit(Map<TopicPartition, OffsetAndMetadata>)` callback that allows the interceptor to rewrite the `OffsetAndMetadata` map before it is committed, enabling programmatic injection of commit metadata. Commit metadata (the string field in `OffsetAndMetadata`) is only settable by callers who construct their own `OffsetAndMetadata` objects; interceptors observing commits have no way to enrich them with cross-cutting metadata like timestamps or trace IDs.

Protocol Impact

OffsetCommit

Details