Returns the custom spacing, in points, between a specified view in the stack view and the view that follows it.
- macOS 10.9+
The view whose trailing spacing you are getting.
The number of points between the trailing edge of the specified view and the one that follows it (that is, the one with the next highest index order).
A stack view retains custom spacing across layout updates. Custom spacing for a view is lost if you remove the view from the stack view or specify a new value.