@Override
    public <PS extends Serializer<P>, P> KeyValueIterator<K, V> prefixScan(final P prefix, final PS prefixKeySerializer) {
        Objects.requireNonNull(prefix, "prefix cannot be null");
        Objects.requireNonNull(prefixKeySerializer, "prefixKeySerializer cannot be null");
        return new MeteredKeyValueIterator(wrapped().prefixScan(prefix, prefixKeySerializer), prefixScanSensor);
    }
@Test
    public void shouldThrowNullPointerOnPrefixScanIfPrefixIsNull() {
        setUpWithoutContext();
        final StringSerializer stringSerializer = new StringSerializer();
        assertThrows(NullPointerException.class, () -> metered.prefixScan(null, stringSerializer));
    }