These aren't used anymore. Any notification which gets moved from
waiting to displayed, will have set the start field with the current
monotonic time.
So testing start == 0 won't ever succeed in
queues_notification_is_finished, as the tested notification is contained
in the displayed queue. So the start field never will be 0.
Also there's no semantics for start being 0 in dunst actually
implemented.
93f6eb58a3