public Optional<Integer> lastSeenLeaderEpoch(TopicPartition topicPartition) {
        return Optional.ofNullable(lastSeenLeaderEpochs.get(topicPartition));
    }
Request an update for the partition metadata iff we have seen a newer leader epoch. This is called by the client
any time it handles a response from the broker that includes leader epoch, except for update via Metadata RPC which
follows a different code path ({@link #update}).

@param topicPartition
@param leaderEpoch
@return true if we updated the last seen epoch, false otherwise
clients/src/main/java/org/apache/kafka/clients/Metadata.java