Separate Enter Exit transition for each controller

Is this possible to set different enter and exit transition?
For example the _from view_ exit with Fade out and the _to view_ enter with Slide bottom + Fade in.

I couldn't do this with `TransitionChangeHandler` the whole transition applies on both controllers.

Start by reading TransitionChangeHandler and tracing how a transition is applied to both controllers. Confirm how the from-view exit and to-view enter are currently coupled, then define separate transition behavior for each side. Done means the example can use Fade out for the from view and Slide bottom plus Fade in for the to view.

Written by the indexing model from the issue text.