FileSystemException: Exists failed

[scheglov]

See dart-lang/sdk#34108

Is it expected that watcher throws exceptions when directory does not exist, is not accessible, etc?

Analysis Server "handles" errors on the events stream, are all errors / exception delivered there, or is there other way to get there problems from watcher?

  Stream<WatchEvent> get changes =>
      new DirectoryWatcher(_entry.path).events.handleError((error) {},
          test: (error) => error is io.FileSystemException);