свойство contentChanged
final
Если изменилось содержимое, а не только атрибуты, contentChanged равно true.
Реализация
final bool contentChanged;
© 2012 the Dart project authors
Licensed under the BSD 3-Clause "New" or "Revised" License.
https://api.dart.dev/stable/2.19.6/dart-io/FileSystemModifyEvent/contentChanged.html
