@Override
    public boolean persistent() {
        return store.persistent();
    }
@return {@code -1} if the put record is the latest for its key, and {@code Long.MIN_VALUE}
        if the put was rejected (i.e., due to grace period having elapsed for a versioned
        store). If neither, any other long value may be returned.
streams/src/main/java/org/apache/kafka/streams/state/internals/KeyValueStoreWrapper.java