The default value is false.
Setting this value to true allows the UIKit.NSLayoutManager to perform noncontiguous layout. In large documents, this can significantly increase performance, since the layout does not need to performed from the beginning of the document.
Application developers can use the EnsureLayout... methods with noncontiguous methods to confirm that particular portions of the text are being laid out properly.
The UITextView.LayoutManager is instantiated with its NSLayoutManager.AllowsNonContiguousLayout property set to true.