use a monotonic clock for timeouts

[tenderlove]

We should use a monotonic clock for timeouts so that if the time changes
on the system it will not impact the timeout code.

[jdantonio]

@tenderlove Should this method be clock_gettime?

This is a Ruby feature I wasn't aware of until you created this PR so thank you for pointing it out. This solves a problem we've discussed in another issue. A ton of tests are failing, however. Should the method call be this? http://ruby-doc.org//core-2.2.0/Process.html#method-c-clock_gettime

[tenderlove]

Yes it should be. That's what I get for not running the tests. >_<

I'll update the patch

[jdantonio]

No sweat. Our tests take a long time to run. Even I skip them occasionally!

[tenderlove]

Also, this code will result in allocations of floating point objects. If we only care about resolution down to the second, we could do:

irb(main):001:0> Process.clock_gettime Process::CLOCK_MONOTONIC, :second
=> 347802
irb(main):002:0>

Which will only give integers (so they should be allocation free)

[chrisseaton]

this code will result in allocations of floating point objects

Aren't small-enough Floats tagged these days?

[tenderlove]

Aren't small-enough Floats tagged these days?

Actually you're totally right. If they are small enough, they won't be allocated. So nevermind! ✨