The API has never existed in a given platform
(e.g. available in iOS but not in Mac); this property is not
versioned (can only be Platform.{None,Mac,iOS}) and applies
to the entire lifetime (up to present) of a
platform. "Unavailable" may be replaced in future versions
by an "Introduced."
Requirements
Namespace: ObjCRuntime Assembly: Xamarin.iOS (in Xamarin.iOS.dll) Assembly Versions: 0.0.0.0