Get the last-modified time of the file.
Returns a Future<DateTime>
that completes with the date and time when the file was last modified, if the information is available.
Throws a FileSystemException if the operation fails.
Future<DateTime> lastModified();
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/2.0.0/dart-io/File/lastModified.html