@Override
    public long approximateNumEntries() {
        return wrapped().approximateNumEntries();
    }
A wrapper key-value store that serializes the record values bytes as a list.
As a result put calls would be interpreted as a get-append-put to the underlying RocksDB store.
A put(k,null) will still delete the key, ie, the full list of all values of this key.
Range iterators would also flatten the value lists and return the values one-by-one.

This store is used for cases where we do not want to de-duplicate values of the same keys but want to retain all such values.
streams/src/main/java/org/apache/kafka/streams/state/internals/ListValueStore.java