KIP-699 — Update FindCoordinator to resolve multiple Coordinators at a time

Accepted Kafka 3.0 ProtocolAdmin

Extends the `FindCoordinator` RPC to accept a batch of group/transaction IDs and return all their coordinator addresses in a single request. Currently `FindCoordinator` only resolves one coordinator per request, causing O(N) sequential round-trips for Admin API operations like `deleteConsumerGroups` that operate on many groups simultaneously.

Protocol Impact

FindCoordinator v4

Details