Provide an option to log unix timestamp as well

[tonythomas01]

Currently, the intervals configuration are set to log every x seconds and the output starts from 1 making it fit for most cases.

It would be great to have another configuration flag that would log results with the current unix timestamp. I can send a PR from my fork actually if people are interested in this.

[astrofrog]

Sounds good to me!

[bugcy013]

Hi Guys,

very good feature. I am waiting for this feature.

+1

-Dhanasekaran.

[jgehrcke]

Apart from logging the unix timestamp, it's also a good idea I think to log a timestamp coming from a monotonic time source (see e.g. https://github.com/jgehrcke/goeffel#timestamps).