@Override
    public boolean setStatusCode(@Nullable HttpStatus status) {
        if (state() == State.COMMITTED) {
            return false;
        } else {
            statusCode = status != null ? status.value() : null;
            return true;
        }
    }
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