pub fn record_backfill_duration(target: &mut SystemdUnitStats, elapsed_ms: f64)Expand description
Account a timer backfill that produced no stats.
A failed backfill still spent D-Bus time — a dbus_timeout worth of it, if
that is how it failed — so the duration is recorded even though there is
nothing to merge and no fetch to count. Leaving it out would hide the
slowest case from per_unit_loop_ms.