The filename of the file wrapper object
- iOS 4.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
This property contains the file wrapper’s filename, or
nil when the file wrapper has no corresponding file-system node.
The filename is used for record-keeping purposes only and is set automatically when the file wrapper is created from the file system using
init and when it’s saved to the file system using
write (although this method allows you to request that the filename not be updated).
The filename is usually the same as the preferred filename, but might instead be a name derived from the preferred filename. You can use this method to get the name of a child that's just been read. Don’t use this method to get the name of a child that's about to be written, because the name might be about to change; send
key to the parent instead.