T snapshottableAddOrReplace(T object) {
        object.setStartEpoch(snapshotRegistry.latestEpoch() + 1);
        int prevSize = baseSize();
        T prev = baseAddOrReplace(object);
        if (prev == null) {
            updateTierData(prevSize);
        } else {
            updateTierData(prev, prevSize);
        }
        return prev;
    }
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