1) For new proxy or protocol, restart the network and default to
the requested server.
2) Otherwise if we aren't using the requested server, switch to it
3) Otherwise choose a random server if the requested server is
stale and auto_connect is True
As switch_to_interface() now has another user, move the logic
there whereby we close the old interface in order to terminate
subscriptions, in order to have it in one place.
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