@Deprecated
    @Override
    public KStream<K, V> through(final String topic) {
        return through(topic, Produced.with(keySerde, valueSerde, null));
    }
@Deprecated // specifically testing the deprecated variant
    @Test
    public void shouldNotAllowNullProducedOnThrough() {
        final NullPointerException exception = assertThrows(
            NullPointerException.class,
            () -> testStream.through("topic", null));
        assertThat(exception.getMessage(), equalTo("produced can't be null"));
    }