@Override
  public R transform(final K readOnlyKey, final GenericRow value) {
    return delegate.transform(
        readOnlyKey,
        value,
        context.orElseThrow(() -> new IllegalStateException("Not initialized"))
    );
  }
@Test(expected = IllegalStateException.class)
  public void shouldThrowOnTransformIfNotInitialized() {
    // Given:
    ksTransformer = new KsValueTransformer<>(ksqlTransformer);

    // When:
    ksTransformer.transform(KEY, VALUE);
  }