public CorsService build(HttpService delegate) {
        if (delegate.as(CorsService.class) != null) {
            throw new IllegalArgumentException(
                    "decorated with a " + CorsService.class.getSimpleName() + " already: " +
                    delegate);
        }

        return new CorsService(delegate, new CorsConfig(this));
    }
Returns a newly-created {@link CorsService} based on the properties of this builder.
core/src/main/java/com/linecorp/armeria/server/cors/CorsServiceBuilder.java