The proposed credential for this challenge.
- iOS 2.0+
- macOS 10.2+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
This method returns
nil if there is no default credential for this challenge.
If you have previously attempted to authenticate and failed, this method returns the most recent failed credential.
If the proposed credential is not
nil and returns
true when you call its
has method, then the credential is ready to use as-is. If the proposed credential’s
has method returns
false, then the credential provides a default user name, and the client must prompt the user for a corresponding password.