LNPopupController: Technique for dismissing TableView `contentViewController` onDrag

My content view controller’s primary view is a UIScrollView subclass, specifically: UITableVIew. Any advice on what the correct solution is for getting the popupInteractionGestureRecognizer to work simultaneously with its installed panGestureRecognizer so that if the scroll view’s contentOffset is zero, dragging down will dismiss the content view controller?

I have a crude initial attempt, which looks in the tableView’s gesture recognizer array for popupInteractionGestureRecognizer. When the contentOffset is just right ™, it will stop the panGestureRecognizer from beginning.

It works…but not great.

Current attempt

    private override func gestureRecognizerShouldBegin(gestureRecognizer: UIGestureRecognizer) -> Bool {
        // Capture '_popupGesture', if necessary...
        if (gestureRecognizers?.contains(gestureRecognizer) ?? false) == false
            && gestureRecognizer is UIPanGestureRecognizer
            && _popupGesture == nil {
                _popupGesture = gestureRecognizer as? UIPanGestureRecognizer
        } else if gestureRecognizer == panGestureRecognizer {
            if let _ = _popupGesture {
                switch (contentOffset.y + 44.0, panGestureRecognizer.velocityInView(self).y) {
                case (-CGFloat.max...0, 1...CGFloat.max):
                    return false
                default:
                    return true
                }
            }
        }

        return true
    }