How can I determine previous state on entering new state? (state trees)

Hello fellow state tree programmers,

I am wondering what the best way to check, upon entering a new state in a state tree, what was the previous, or source state, from which the new state came from.

I notice that on the event EnterState (see below) there is a Transition struct which contains a variable “Source State” but I can’t seem to get any information from this. “Source State” appears to be a structure with nothing in it. Perhaps it isn’t yet implemented?

Anyways, if anyone has any ideas I would be appreciative.

Have a wonderful day!