public sealed class JobMessageEvent : ArcGIS.Core.Events.CompositePresentationEvent<JobMessageEventArgs<JobMessage>> 

// Subscribe to the job message event to start receiving job and step notifications.
// Use the subscription token to unsubscribe from the event.
var subscriptionToken = JobMessageEvent.Subscribe(e =>
{
  var jobId = e.Message.JobId;
  var msgType = e.MessageType;
  var message = e.Message;
  // Include logic to process the job / step messages
});

// Subscribe to certain jobs. This will add these jobIds to the list of already subscribed jobs.
var notifManager = WorkflowClientModule.NotificationManager;
notifManager.SubscribeToJobs(jobIds);

// Unsubscribe from the job message event using the subscription token
JobMessageEvent.Unsubscribe(subscriptionToken);

// Unsubscribe from jobs using the same instance of Notification Manager used to subscribe to jobs.
// This will remove the jobs from the subscribed job list if no other clients are subscribed to those jobs.
var notifManager = WorkflowClientModule.NotificationManager;
notifManager.UnsubscribeFromJobs(jobIds);