Log progress and estimated finish time

[adamsitnik]

A feature request I got offline from our users who run a LOT of benchmarks (thousands) and would like to know when approximately it's going to finish.

Sample log output:

// ** Remained 17 (94.4%) benchmark(s) to run. Estimated finish 2/2/2022 7:23:32 PM **

cc @danmoseley

[AndreyAkinshin]

I like the idea of printing finish estimates, but I have concerns about presenting it in the form of "finish date/time". Typically, I run benchmarks on different cloud machines with different time zones. Using the current approach, I have to be aware of the time zone on a specific machine and make some additional manual calculations transforming the server finish time to my local time zone.

I think it would be better to print just the estimated time to finish in a human-readable format (something like 5 hours 25 minutes).

[adamsitnik]

@AndreyAkinshin I prefer to have the exact finish date, so perhaps we should print both?

- // ** Remained 17 (94.4%) benchmark(s) to run. Estimated finish 2/2/2022 7:23:32 PM **
+ // ** Remained 17 (94.4%) benchmark(s) to run. Estimated finish 2/2/2022 7:23:32 PM (5h 25m from now) **

[AndreyAkinshin]

@adamsitnik

so perhaps we should print both?

LGTM.
However, could we specify the date format as yyyy-mm-dd? Dates like 2/3/2022 are confusing because they could mean February-03 or March-02. Also, it would be nice to have a fixed platform-independent format.

[adamsitnik]

@AndreyAkinshin done, PTAL:

// ** Remained 13 (72.2%) benchmark(s) to run. Estimated finish 2022-02-03 15:20 (0h 3m from now) **