System.currentTimeMillis()

[cgay]

Should have some equivalent to System.currentTimeMillis(). In other words, "get me an integer that represents 'now' which I can stash away and compare to later." Wanted this for Dylox's clock() implementation.

[cgay]

In time@0.1.1 I pushed some changes I'd made a while back to get basic macOS support working. I simply used CLOCK_MONOTONIC instead of the _RAW version, however I think the right fix is to use CLOCK_UPTIME_RAW based on this post: https://reviews.llvm.org/D27429

While I'm here... Java now has System.nanoTime() as well, and we might want something like that in addition to (or instead of) something like System.currentTimeMillis().

[cgay]

There's a nice write-up of the issues here: ros2/rcutils#43 (comment)

And more useful discussion here: https://groups.google.com/g/golang-nuts/c/YYi57cFhnL4

And this Python PEP is referenced by the above golang thread: https://peps.python.org/pep-0418/#monotonic-clocks (lots of useful reading here)

The summary seems to be "this is hard"....