Link extensions-related: link availability/expiry?

[Mo McRoberts <mo@xxxxxxxxxx>]

Hi list,

This isn't *directly* relevant to the link extensions draft, but does
lie along the same lines.

I'm looking for a pair of attributes which can be applied to an
atom:link which will indicate "not available until" and "not available
after" with regards to the linked resource. Does anybody know of
anything vaguely (be it official or de facto) standard?

I have a specific use-case in mind (indicating the availability of a
TV or radio programme for on-demand/'catch-up' playback), but I'm sure
there will likely be others, so if there's nothing out there
already...

Any pointers would be much appreciated!

M.