@Override
    public KTable<K, Long> count() {
        return doCount(NamedInternal.empty(), Materialized.with(keySerde, Serdes.Long()));
    }
@Test
    public void shouldThrowNullPointerOnCountWhenMaterializedIsNull() {
        assertThrows(NullPointerException.class, () ->  groupedStream.count((Materialized<String, Long, KeyValueStore<Bytes, byte[]>>) null));
    }