@Override
    @Nullable
    public HttpStatus getStatusCode() {
        if (statusCode != null) {
            return HttpStatus.resolve(statusCode);
        }
        final Integer statusCode0 = getStatusCode0();
        if (statusCode0 != null) {
            return HttpStatus.resolve(statusCode0);
        }
        return null;
    }
Set the HTTP status code of the response.
Note that this method is only valid for Spring 5. {@code HttpStatusCode} is used as the input type in
Spring 6.
spring/boot2-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/AbstractServerHttpResponseVersionSpecific.java