Want to understand the additionalSafeAreaInsets property and insetsLayoutMarginsFromSafeArea usage, follow the video introduced the way to try a few times, but can not achieve the effect of video, insetsLayoutMarginsFromSafeArea no effect, even if set to false views still part of the offset.
Video address: https: //developer.apple.com/videos/play/wwdc2017/204/, in about 27 minutes.
