@Override
        @Nullable
        public String url() {
            return ctx.request().uri().toString();
        }
This sets the client IP:port to the {@link RequestContext#remoteAddress()}
if the {@linkplain #parseClientIpFromXForwardedFor default parsing} fails.
brave/brave6/src/main/java/com/linecorp/armeria/server/brave/ServiceRequestContextAdapter.java