As per the Apple developer documentation:
> Prefer to use the equivalent clock_gettime_nsec_np(CLOCK_UPTIME_RAW) in
> nanoseconds.
and also
> This API has the potential of being misused to access device signals to try
> to identify the device or user, also known as fingerprinting. Regardless of
> whether a user gives your app permission to track, fingerprinting is not
> allowed. When you use this API in your app or third-party SDK (an SDK not
> provided by Apple), declare your usage and the reason for using the API in
> your app or third-party SDK’s PrivacyInfo.xcprivacy file.
see https://developer.apple.com/documentation/kernel/1462446-mach_absolute_time