Program acmefocused is a server that tells acme's focused window ID to clients.
Acmefocus will listen on a unix domain socket at NAMESPACE/acmefocused. The window ID is written to a client and the connection to the client is closed immediately. The window ID is useful for acme clients that expects $winid environment variable to be defined but it is being run outside of acme.
$ acme & $ acmefocused & $ dial $(namespace)/acmefocused 1 $