private long pollFollower(long currentTimeMs) {
        FollowerState state = quorum.followerStateOrThrow();
        if (quorum.isVoter()) {
            return pollFollowerAsVoter(state, currentTimeMs);
        } else {
            return pollFollowerAsObserver(state, currentTimeMs);
        }
    }
Attempt to send a request. Return the time to wait before the request can be retried.
raft/src/main/java/org/apache/kafka/raft/KafkaRaftClient.java