default SELF decorator(DecoratingHttpServiceFunction decoratingHttpServiceFunction) {
        requireNonNull(decoratingHttpServiceFunction, "decoratingHttpServiceFunction");
        return decorator(
                delegate -> new FunctionalDecoratingHttpService(delegate, decoratingHttpServiceFunction));
    }
Decorates an {@link HttpService} with the specified {@code decorator}.

@param decoratingHttpServiceFunction the {@link DecoratingHttpServiceFunction} that decorates
                                     {@link HttpService}s
core/src/main/java/com/linecorp/armeria/server/ServiceConfigSetters.java