Re: [ServiceWorker] spec should be more explicit about accessing internal body on opaque Responses (#710)

* Used "internal response" to set the body to null for a HEAD request in `matchAll(request, options)`
* Set the Response's Headers' guard to "immutable" in `addAll(requests)` and to the input Response's guard value in `put(request, response)`

I believe more filtered response bits for foreign fetch are being followed up in https://github.com/slightlyoff/ServiceWorker/issues/841 and we'll continue to discuss there.

Closing.

---
Reply to this email directly or view it on GitHub:
https://github.com/slightlyoff/ServiceWorker/issues/710#issuecomment-194708835