`fs.unlink()` is used as if it was synchronous when deleting a stale UNIX socket

[matteomonti]

In lib/sockets/sock.js, line 385, you handle the case of a pre-existing UNIX socket: you check if it's stale by connecting and if it is you delete it. However, in order to do that, you call fs.unlink(port), which is an asynchronous function.

This results in a deprecation error and possibly undefined behavior.

You might want to either switch to fs.unlinkSync or provide a callback to fs.unlink and move self.server.listen(port, host, fn) to the callback.