* Make the consumer-count int32 atomic, avoiding the need for
all get/put operations to go through a global lock.
* Disable the code that unloads the stack interface when there
are no consumers. Otherwise, we wind up repeatedly loading/
unloading the stack interface during the boot process (e.g.
while sockets are being created and destroyed during net_server
startup.)
In the future, if we want to really unload it, we can add some
interaction with low_resource_monitor or something like that.
Reduces register_domain call count during boot from 31 to 7
(it appears the stack was loaded and unloaded 5 times, before
it stayed loaded the 6th.)
Augustin Cavalier
61eed15db9