Stopping a service closes its listener, and a closed listener answers Accept
with core's listener.ErrClosed — which the guard never matched (it knew only
net.ErrClosed), so every stop reached the log at error level and read like a
crash. The tun handler logged the same shape a second time: its client wrapped a
closed device with %s, throwing the cause away, so the caller could not tell a
device closed under the reader from a real read failure. %w keeps the chain and
the handler logs the closed case at debug.