[ServiceWorker] Support restarting download when storing large resources in Cache (#713)

Recently I noticed that a website was using SW+Cache to offline its app shell, but it was using FileSystem API to store its videos:

  http://richapps.de/taking-the-web-offline-service-worker/

What features might be missing to force the use of FileSystem?

It seems one might be the ability to start downloading a large resource, start it streaming into Cache, network interruption occurs, and then continue the download when network is restored.

I believe Cache currently rejects the cache.put() or cache.add() if the body errors out.  (Or rather its currently vaguely spec'd.)  There is definitely no way to continue a partially stored download, though.

Thoughts?

@jakearchibald @annevk 

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Reply to this email directly or view it on GitHub:
https://github.com/slightlyoff/ServiceWorker/issues/713