private boolean isUpdateNeeded(EpochEntry entry) {
        return latestEntry().map(epochEntry -> entry.epoch != epochEntry.epoch || entry.startOffset < epochEntry.startOffset).orElse(true);
    }
Assigns the supplied Leader Epoch to the supplied Offset
Once the epoch is assigned it cannot be reassigned
storage/src/main/java/org/apache/kafka/storage/internals/epoch/LeaderEpochFileCache.java