@Override
    public boolean setFlushListener(final CacheFlushListener<K, ValueAndTimestamp<V>> listener,
                                    final boolean sendOldValues) {
        return false;
    }
This class is a generic version of the in-memory key-value store that is useful for testing when you
 need a basic KeyValueStore for arbitrary types and don't have/want to write a serde
streams/src/test/java/org/apache/kafka/test/GenericInMemoryTimestampedKeyValueStore.java