@Override
    public void beforeCommit(Supplier<? extends Mono<Void>> action) {
        commitActions.add(action);
    }
Return the underlying server response.

<p><strong>Note:</strong> This is exposed mainly for internal framework
use such as WebSocket upgrades in the spring-webflux module.
spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/AbstractServerHttpResponse.java