StackView Hide With Animation Bug Example

This is a bug that exists in iOS 10.2+ (didn't check on previous versions).

Description:

When hiding an arrangedSubview of an UIStackView using UIView animation API multiple times, the isHidden property values "stack" and it requires settigns isHidden to false multiple times before the value updates.

Steps to reproduce:

1. Add an arranged subviews to UIStackView
2. Call isHidden = true the subview within a UIView animation block multimple times
3. Call isHidden = false on the same subview
4. Observe that it doesn't appear and still has isHidden still set to true
5. Call isHidden = false until the value of the property actually changes to false