timeout for pacman cache server

Pacman recently added support for cache servers (!98, thanks for that). I use them in my LAN at home: my PC as server and my laptop as client. This works fine unless I turn off my PC or leave my home with my laptop for a friend/uni/... This causes noticable delay (like 4s per package) when updating or installing a new package. I would like to time out connections to a cache server after ~100ms when the initial connection to that cache server fails and remove it from the list of available cache servers because it won't magically teleport to my friend/uni. There is a similar issue #36 asking that for mirror servers but this is for cache servers.