Add option to show timings for each command in cli and also return timings when used programmatically

[eliasm307]

It would be useful if the package tracked the start and end times of processes and/or the calculated duration in ms, then returning this as part of ExitInfos for programmatic use or printing to terminal when a timing option is enabled.

[gustavohenke]

For the CLI, you can run your command with time <command>, or instead you can set your prefix to be a timestamp, which should give some insights too:

$ concurrently -p "{time}" "echo hi; sleep 1; echo bye"
2021-10-28 20:01:01.644 hi
2021-10-28 20:01:03.953 bye
2021-10-28 20:01:03.955 echo hi; sleep 1; echo bye exited with code 0

That said, the API doesn't provide this, so your idea still is a good one.

[eliasm307]

@gustavohenke yes the timestamp prefixes are an option however when there are multiple processes that produce a lot of logs it's difficult to manually calculate the durations of the processes. I feel it would be a better experience if there was an option to log this at the end as a summary

[eliasm307]

I'm not available for the near future but I would be interested in giving this a go if its still open when I'm free