> It's a weird example, because it moves listener creation elsewhere, which is not always possible (e.g. consider if the goroutine would be spawning an external program instead of setting up the listener of its own).

Just addressing the case of spawning an external program: if you have control of the external program you’re spawning it can be better to pass the listening socket in using the systemd $LISTEN_PID protocol. It’s easy too implement, language independent and you get systemd integration for free.

See also: https://blog.williammanley.net/2014/01/26/Improve-integratio...