Should FileManager.attributesOfItem(atPath:) expose ADS on Windows?

[jakepetroules]

Should FileManager.attributesOfItem(atPath:) and similar APIs expose Alternate Data Streams on Windows? They're somewhat logically equivalent to extended attributes on Unix-y platforms, so it might make sense.

[jmschonfeld]

If they are logically equivalent to extended attributes then to me it'd make sense to provide them in the same manner that we provide extended attributes on Unix platforms.

However attributesOfItem(atPath:) does not provide extended attributes on Unix platforms as API either so this isn't a lack of functionality for Windows in specific but a lack of API in general. It could be possible to add a new FileAttributeKey that exposes a value that represents xattrs on Unix and ADS on Windows in a cross-platform manner (ignoring it on platforms that don't support xattrs like WASI and Android)