applicationFolder function
Where appName keeps its documents on this platform, as a path — for an
application offering to show somebody the folder a write failed in.
Null where the platform keeps nothing, the same answer applicationDirectory gives; the web build's own copy of this returns null always, since a browser has no folder to show.
Implementation
String? applicationFolder(String appName) => applicationDirectory(
appName: appName,
platform: defaultTargetPlatform,
environment: Platform.environment,
temporary: Directory.systemTemp.path,
);