比在func外部使用var跟踪设备方向更好的方法？

Note: The non-specific solution being sought here is how to avoid triggering code if the screen size hasn't changed, e.g. flipping an iPad on its Y-axis (from landscapeLeft to landscapeRight) to show a view to someone without it resizing. In other words, the view will rotate without resizing anything). The test essentially verifies that no intermediate rotation to a different orientation occurred.Note: The non-specific solution being sought he