Re: Suggestion: Partial file transfer.

I'd be more comfortable with this and other proposals if the original
data were delivered with a 'content-ID' that was unique to the
particular content being delievered, and any follow-up request for
partial delivery were indexed not by the original URL but by the
content-ID itself. (The lack of a content-ID would be a signal that
the object wasn't suitable for partial transmission or that the server
didn't support such.)

The content-ID could also be used as a GET IF-DIFFERENT key, since the
content-ID would change when the content changed. Content-ID is
required to be globally unique. (It might even be a URN, but who
knows?)