Sitecore The type or namespace name ‘Job’ does not exist in the namespace ‘Sitecore.Jobs’ (are you missing an assembly reference?)

  public IEnumerable<Sitecore.Abstractions.BaseJob> Jobs
  {
    get
    {
      return Sitecore.Jobs.JobManager.GetJobs().OrderBy(job => job.QueueTime);
    }
  }

  protected string GetJobMessages(Sitecore.Jobs.DefaultJob job)
  {
    System.Text.StringBuilder sb = new StringBuilder();
    if (job.Options.ContextUser != null)
      sb.AppendLine("Context User: " + job.Options.ContextUser.Name);
    sb.AppendLine("Priority: " + job.Options.Priority.ToString());
    sb.AppendLine("Messages:");
    foreach (string s in job.Status.Messages)
      sb.AppendLine(s);
    return sb.ToString();
  }

string jobName = "MyJob"

DefaultJobOptions options = new DefaultJobOptions(jobName, "Update", Sitecore.Context.Site.Name, this, "Update", new object[] { }) { ContextUser = Sitecore.Context.User, Priority = System.Threading.ThreadPriority.Normal };

JobManager.Start(options);

Sitecore.Abstractions.BaseJob job = JobManager.GetJob(jobName);
job.Status.State = JobState.Running;
job.Status.Total = 42;