如果UITextView是第一个子视图，那么在视图顶部和文本开头之间会出现一个大空间

It appears that like in native X Code, in Xamarin studio for ioS if your first sub-view in a view heirarchy is a UITextView, then adding a top-layout constraint to this view will cause a large block of empty space to appear at the top of the scroll view.It appears that like in native X Code, in Xamar