@SuppressWarnings("unchecked")
    public <T> Optional<LeaderState<T>> maybeLeaderState() {
        EpochState fixedState = state;
        if (fixedState instanceof LeaderState) {
            return Optional.of((LeaderState<T>) fixedState);
        } else {
            return Optional.empty();
        }
    }
Become a follower of an elected leader so that we can begin fetching.
raft/src/main/java/org/apache/kafka/raft/QuorumState.java