The difference in CLOCK_MONOTONIC behavior between Linux and Darwin (Apple) systems was an issue when they added Clock to the Swift standard library. It led to

The difference in CLOCK_MONOTONIC behavior between Linux and Darwin (Apple) systems was an issue when they added Clock to the Swift standard library. It led to the two built-in clock implementations being named SuspendingClock and ContinuousClock, rather than UptimeClock and MonotonicClock.