closing file connexions

[David Vinayak Wallace <Gumby@MIT-MC>]

In Symbolics 3600 Zwei in Release 6.0, IP-TCP 29.0, AISite 9.1,
microcode TMC5-MIC 319, on Lisp Machine Jimi Hendrix:

There ought to be a M-X Close Connection (even a command chewer
command would suffice) for those systems which charge for connect time
(like multics).

It would be nice if there were a way to mark such hosts (perhaps by
putting something in their namespace object) -- the file job lifetime
could be exteremely short in this case.