ScrollView panGestureRecognizer distinguish between scrolling and via scroll bar

iOS 13 introduced a new way to scroll within a scrollview - you can now touch and hold on a scroll bar, then drag to scroll.

I'm trying to add some logic to the panGestureRecognizer of a scrollview.

I attached my own handler via [scrollView.panGestureRecognizer addTarget: action:].

Both cases fire through panGestureRecognizer - but I can't see a way to distinguish which scrolling mode was active.

I attempted to monitor the velocity of the panGestureRecognizer and which way the scrollview is responding - with the idea that when using the scrollbar, these directions oppose each other. But this is flaky, and has false positives and negatives.
Could you detect the location of touch in the began handler (because it is a continuous gesture), hence knowing if you tapped in the scroll or not.
Then keep this value in a property of the class.
Use this property to act accordingly in the action.
@Claude31 I'm looking for a method that doesn't rely on heuristics. I've currently got something working with a heuristic, but it has a lot of false positives.

(I would provide code for my heuristic, but it only works for my specific case - not finding if the scroll bar is active in general)
ScrollView panGestureRecognizer distinguish between scrolling and via scroll bar
 
 
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