boolean snapshottableAddUnlessPresent(T object) {
        T prev = baseGet(object);
        if (prev != null) {
            return false;
        }
        object.setStartEpoch(snapshotRegistry.latestEpoch() + 1);
        int prevSize = baseSize();
        baseAddOrReplace(object);
        updateTierData(prevSize);
        return true;
    }
Iterate over the values that existed in the hash table during a specific snapshot.

You can use this iterator even if you are making changes to the map.
The snapshot is immutable and will always show up the same.
server-common/src/main/java/org/apache/kafka/timeline/SnapshottableHashTable.java