@Override
    public HttpResponse serve(ServiceRequestContext ctx, HttpRequest req) throws Exception {
        final Queue<HttpService> delegates = ctx.attr(DECORATOR_KEY);
        assert delegates != null;
        final HttpService delegate = delegates.poll();
        assert delegate != null;
        return delegate.serve(ctx, req);
    }
Adds the specified {@code prefix} to this {@code decorator}.
core/src/main/java/com/linecorp/armeria/internal/server/RouteDecoratingService.java