sendOutlineNotification method
If the plugin provides outline information, send an outline notification
for the file with the given path to the server.
Implementation
@override
Future<void> sendOutlineNotification(String path) async {
  try {
    var request = await getOutlineRequest(path);
    var generator = OutlineGenerator(getOutlineContributors(path));
    var generatorResult = generator.generateOutlineNotification(request);
    generatorResult.sendNotifications(channel);
  } on RequestFailure {
    // If we couldn't analyze the file, then don't send a notification.
  }
}