code: public CorsService build(Service<HttpRequest, HttpResponse> delegate) {
          if (delegate.as(CorsService.class).isPresent()) {
              throw new IllegalArgumentException(
                      "decorated with a " + CorsService.class.getSimpleName() + " already: " +
                      delegate);
          }
  
          return new CorsService(delegate, new CorsConfig(this));
      }
docs: Returns a newly-created {@link CorsService} based on the properties of this builder.