During the discussion of [Pitch] Clock, Instant, Date, and Duration, distributed actors and the ability to define deadlines for remote computers have been presented as motivation for some additions to the stdlib.
That thread is already quite long, but I'm really curious how exactly coordination is supposed to work ([Pitch] Clock, Instant, Date, and Duration - #256 by Tino).
To sum it up (as far as I understand it):
It's stated that deadlines shall be transferred as absolute time (UTC), relying on NTP for ensuring a common baseline.
However, I don't understand how this is supposed to work:
I guess for devices like iPhones, we can assume pretty high precision due to GPS — but I think most servers don't have GPS, and you can't even enforce proper NTP-sync.
I'm definitely not an expert, but I think distributed actors will either have to use durations to specify timeouts (that's not an option for reasons beyond my understanding), have some internal mechanism to keep track of deltas — or require that the involved computers take care for common time themselves (thus causing errors when system clocks are out of sync).
How is this handled in existing solutions, or am I missing something and there's no problem here at all?