public double Duration {get;}

{
  TaskStartedEvent.Subscribe(taskStartedEventArgs =>
  {
    string userName = taskStartedEventArgs.UserID;    // ArcGIS Online signed in userName.  If not signed in to ArcGIS Online then returns the name of the user logged in to the Windows OS.
    string projectName = taskStartedEventArgs.ProjectName;

    Guid taskItemGuid = taskStartedEventArgs.TaskItemGuid;
    string taskItemName = taskStartedEventArgs.TaskItemName;
    string taskItemVersion = taskStartedEventArgs.TaskItemVersion;

    Guid taskGuid = taskStartedEventArgs.TaskGuid;
    string taskName = taskStartedEventArgs.TaskName;

    DateTime startTime = taskStartedEventArgs.StartTime;
  });
  TaskEndedEvent.Subscribe(taskEndedEventArgs =>
        {
          string userName = taskEndedEventArgs.UserID;    // ArcGIS Online signed in userName.  If not signed in to ArcGIS Online then returns the name of the user logged in to the Windows OS.
          string projectName = taskEndedEventArgs.ProjectName;

          Guid taskItemGuid = taskEndedEventArgs.TaskItemGuid;
          string taskItemName = taskEndedEventArgs.TaskItemName;
          string taskItemVersion = taskEndedEventArgs.TaskItemVersion;

          Guid taskGuid = taskEndedEventArgs.TaskGuid;
          string taskName = taskEndedEventArgs.TaskName;

          DateTime startTime = taskEndedEventArgs.StartTime;
          DateTime endTime = taskEndedEventArgs.EndTime;
          double duration = taskEndedEventArgs.Duration;

          bool completed = taskEndedEventArgs.Completed;    // completed or cancelled
        });
}