A string containing the domain for this service.
- iOS 2.0+
- macOS 10.2+
- Mac Catalyst 13.0+
- tvOS 9.0+
This can be an explicit domain name or it can contain the generic local domain name,
@"local." (note the trailing period, which indicates an absolute name).
This property’s value is set when the object is first initialized, whether by your code or by a browser object. See
init(domain: for more information.