pub(crate) fn current_user_id(sys: &System) -> Option<String>Expand description
The OS user id owning the calling process, used to place a target window on the near or far side of the T3 boundary.
Fails CLOSED, matching own_instance_pids()’s existing discipline: if this
returns None every window resolves to OtherUser and capture is denied.
An unresolvable owner is exactly the case where guessing “probably mine”
would be how a cross-user capture slips through.