Get timestamp in miliseconds

I have looked in most of the date/time related UDFs I could find, but nowhere I have been able to find an answer to my simple question: how do I return the current date/time including miliseconds ?

Something like this in Delphi:

; http://www.delphibasics.co.uk/RTL.asp?Name=FormatDateTime
$mydatestring = FormatDateTime(_NowTime(), "hh:nn:ss.zzz")
This would return current time formatted like 09:48:33.124

Reason is a wish to log network communication, and show time remote machine takes to respond. The communication may take place up to 20 times per second, so I don't want 20 x same time stamp.

Not sure if Windows is able to report this back. There does not seem to be any miliseconds in Windows strftime.

So, is it possible ? I know I can use timerdiff and sleep() will also work with higher resolution than seconds.
But here, I need the absolute time. And while I _could_ use _nowtime() + timerdiff(start_of_script), I would consider this a hack and last resolution.