loop.create_unix_server() should remove socket at that path if it exists. Every application that wants to use unix socket server should do that. Why not to add code that removes unix socket before binding ?

It should:

1. Check if it is exists and that is UNIX socket (i.e. do os.stat())
2. raise exception if removal failed, raise exception if this path exists but is not unix socket.
3. not even try to remove if path starts with zero byte (i.e. abstract unix socket)