public CoordinatorResult<HeartbeatResponseData, CoordinatorRecord> classicGroupHeartbeat(
        RequestContext context,
        HeartbeatRequestData request
    ) {
        return groupMetadataManager.classicGroupHeartbeat(
            context,
            request
        );
    }
Handles a classic group HeartbeatRequest.

@param context The request context.
@param request The actual Heartbeat request.

@return A Result containing the heartbeat response and
        a list of records to update the state machine.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupCoordinatorShard.java