[packagekit] Yum backend throttling

[Richard Hughes]

skvidal mentions we can throttle the download:
http://hughsient.livejournal.com/38322.html?thread=303794

This would be great. Apparently there's stuff in the YumRepository
object. I think 40% might be a good metric.

Can a python dude tell me how easy this is? The first to reply gets to
implement this :-)

Thanks.

Richard.

p.s. All contributors get Christmas cards. Really.