@Override
    public WindowStoreIterator<V> backwardFetch(final K key,
                                                final long timeFrom,
                                                final long timeTo) {
        Objects.requireNonNull(key, "key cannot be null");
        return new MeteredWindowStoreIterator<>(
            wrapped().backwardFetch(keyBytes(key), timeFrom, timeTo),
            fetchSensor,
            iteratorDurationSensor,
            streamsMetrics,
            serdes::valueFrom,
            time,
            numOpenIterators,
            openIterators
        );
    }
@Test
    public void shouldThrowNullPointerOnBackwardFetchIfKeyIsNull() {
        assertThrows(NullPointerException.class, () -> store.backwardFetch(null, 0L, 1L));
    }