In addition to writing, I haven't been successful in reading the filename or preferredFilename in a DocumentGroup
either...
init(configuration: ReadConfiguration) throws {
let filename = configuration.file.filename
let preferredFilename = configuration.file.preferredFilename
[...]
}
...Here filename & preferredFilename always returns nil even if the the file has been named by the user before the document is opened.
(I am able to read and write the filenames of Child FileWappers, but the 'root' filewrapper's filename seems always inaccessible.)