Replacing `Date`

[fabianfett]

We need to discuss how we want to replace Date if we don't want to link against Foundation at all. The problem is that we get a Deadline from AWS:

Lambda-Runtime-Deadline-Ms – The date that the function times out in Unix time milliseconds.
Source: https://docs.aws.amazon.com/lambda/latest/dg/runtimes-api.html

Users of this library might want to know how much time they have left to execute their function. Since I can't see a way to get access to the Unix time in milliseconds, it seems like we have to import <time.h>.

https://pubs.opengroup.org/onlinepubs/7908799/xsh/clock_gettime.html

I've never wrapped a C call before, so this is something I'd be interested in trying if this is a way forward for us.

[tomerd]

maybe use DispatchWallTime?

[fabianfett]

That was my first guess after looking into TimeAmount and Deadline.

But studying the documentation I couldn't see a way to set the time to 1970-01-01. But if you know a way I'm definitely in favour of this approach.

[tomerd]

maybe https://developer.apple.com/documentation/dispatch/dispatchwalltime/2300027-init?