@Override
  public KeyValue<KOutT, GenericRow> transform(final KInT key, final GenericRow value) {
    return KeyValue.pair(
        keyDelegate.transform(
            key,
            value,
            context.orElseThrow(() -> new IllegalStateException("Not initialized"))
        ),
        valueDelegate.transform(
            key,
            value,
            context.orElseThrow(() -> new IllegalStateException("Not initialized"))
        )
    );
  }
@Test
  public void shouldReturnValueFromInnerTransformer() {
    // When:
    final KeyValue<String, GenericRow> result = ksTransformer.transform(KEY, VALUE);

    // Then:
    assertThat(result, is(KeyValue.pair(RESULT_KEY, RESULT_VALUE)));
  }