public ThrottlingService build(HttpService delegate) {
        return new ThrottlingService(requireNonNull(delegate, "delegate"), getStrategy(),
                                     getAcceptHandler(), getRejectHandler());
    }
Returns a newly-created {@link ThrottlingService} based on the {@link ThrottlingStrategy}s added to
this builder.
core/src/main/java/com/linecorp/armeria/server/throttling/ThrottlingServiceBuilder.java