I am having difficulty understanding conceptually the best way of implementing the following:
I have a UIScrollview embedded within ViewControllerB that has been presented by ViewControllerA.
Once the user has scrolled to the top of the UIScrollview, when he attempts to pull down more when there is nothing further to scroll, I want this "dragging" motion to pull down and dismiss the current ViewControllerB, leaving ViewControllerA on display.
How can I trigger that interactive transition of panning down ViewControllerB from within the UIScrollView's dragging mechanism once reaching the top?