Kroah-Hartman: AF_BUS, D-Bus, and the Linux kernel

don't get me wrong, i wasn't saying the plumber solved this problem, i
just think it solves a similar problem. and it's worth considering if
some of the mechanism might be right for this problem.

there are a few reasons this is never a problem on plan 9
1. private namespaces. each user has his own set of private namespaces.
users don't interfere with one another.
2. on a shared machine, the user imports the plumber from their terminal,
so if they plumb a pdf, the viewer starts on the terminal.