[Exim] Some kind of mailserver stress test needed

Hi,
I am using exim 3.35 (GNU/Debian stable) and looking for some kind of
mailserver stresstest. I want to evaluate how my mailserver scales under
high load and how much mail-traffic it can handle.
I've searched the web as well as the list-archives but i couldn't find
anything that goes into that direction.
Any hint would be greatly appreciated.

Mit freundlichen Gruessen / Best regards
Dominik Schulz