Tracking health regen

[Headhuntress]

I'm trying to find a way to track whatever healing is done by the troll in-combat health regen. It seems like it doesn't fire a combat log event, or at least not with the player as the source. I guess it does fire a UNIT_HEALTH event, but there's no way to confirm it's health regen causing it (unless perhaps there is a way to find the amount you regen per tick and compare the number). Is there actually a solution to this? I can only find power regen related functions in the API.