code: @SuppressWarnings("unchecked")
      private static Function<Service<HttpRequest, HttpResponse>,
              ? extends Service<HttpRequest, HttpResponse>> newDecorator(Decorator decorator) {
          return service -> service.decorate(getInstance(decorator, DecoratingServiceFunction.class));
      }
docs: Returns a new decorator which decorates a {@link Service} by the specified
  {@link Decorator}.