Doesn't this risk breaking concurrency features of support for streaming chunks ? The override of headers is probably the only use case for which extending AsyncResponse is aworking solution.

So if we don't make AsyncResponse final anymore, maybe a bunch of its methods should become final instance, to prevent overriding them by thinking that it will work while it would break half of the ways the client can be used. Any of the methods dealing with the content cannot be used to implement additional logic without breaking the streamed usage.

Let's make getContent, toArray and toStream final? The rest should be fine being extended.

@nicolas-grekas done ✅

Thank you@lyrixx.