Overridden by subclasses to substitute another object for itself during keyed archiving.
- iOS 2.0+
- macOS 10.2+
- tvOS 9.0+
- watchOS 2.0+
A keyed archiver creating an archive.
The object encode instead of the receiver (if different).
This method is called only if no replacement mapping for the object has been set up in the encoder (for example, due to a previous call of
replacement to that object).