Per-resource preferences

[chrysn]

Discussion around location-scheme in https://github.com/core-wg/href/pull/81/files indicated that there might indeed be a need for per-resource preferences for particular transports.

I'm not convinced this is something that should be ever advertised, but @cabo, you seem to have use cases in mind, so let's discuss this here: Is there a concrete example you think of, if not to fix my lack of imagination then at least to have a concrete example?

[chrysn]

Personally, I don't think Location-Scheme (and -Host and -Port) is how it should be done, but if discussions wind up with having Location-* be preferred, this document can add them (and, given the time lines, already in a CRI fashion)