@Override
    @Nullable
    public HttpStatusCode getStatusCode() {
        if (statusCode != null) {
            return statusCode;
        }
        final Integer statusCode0 = getStatusCode0();
        if (statusCode0 != null) {
            return HttpStatusCode.valueOf(statusCode0);
        }
        return null;
    }
Set the HTTP status code of the response.
Note that this method is only valid for Spring 6. Spring 5 takes {@link HttpStatus} as the input type.
spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/AbstractServerHttpResponseVersionSpecific.java