Proposal: support ServerTiming in http response

[AnnatarHe]

Hi @jasonraimondi ,

I noticed that the ServerTiming exists in web standard. Do you have any plan to support this feature? since the headless browser is slow. maybe it's useful to find potential performance issues.

for example:

alloc;dur=100,
webpage.goto;dur=20.1,
webpage.screenshot;dur=322.222,
resize;dur=189

[jasonraimondi]

This is pretty interesting, I haven’t heard of it before, but it looks like it could be useful. I’ll take a look into this when I get some free time.