Visual Test timer results to txt file

Hi, 

I'm trying to collect timer results from runs to a one txt file. What would be the best way to do this. 

I would like it to have date, time and timer result, so to look like something like this: 

31.08.2018 09:55 the timer run for 7.300 seconds

31.08.2018 10:55 the timer run for 7.510 seconds

I use silk test workbench and visual tests.

Thank you!