The character position at which the receiver will begin its next scanning operation.
- iOS 2.0+
- macOS 10.0+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
index is beyond the end of the string being scanned.
This property is useful for backing up to rescan after an error.
Rather than setting the scan location directly to skip known sequences of characters, use
scan, which allow you to verify that the expected substring (or set of characters) is in fact present.