🚀 go-pugleaf

When a task dies all port rights that it holds are deallocated. 
Therefore, if a task T has a receive right for a port A which has a
backup port B, then when T dies the receive right for A will be sent to
B in a notification message.

However, backup ports do not work across the network in some cases.  In
the above scenario, the receive right for B can be on a second machine
and everything works.  However, if T's machine crashes, and the receive
right for B is on a second machine, then the backup port mechanism will
not work.  This is because netmsgservers don't know about backup ports,
and if T's kernel doesn't generate the notification message (because it
crashed), then the netmsgservers on the other machines won't know to
synthesize the notification message and port A will be destroyed.

Backup ports are not designed to be The Robustness Solution.  They are a
substitute for some uses of ownership rights, a feature I removed.  (The
good thing about ownership rights is that netmsgservers do know about
them, so they work even when machines crash.  The bad thing about
ownership rights is that this greatly complicates netmsgservers.)

Rich