public bool IsLabelVisible {get;}

{
    //Note: needs to be called on the MCT
    // toggle the label visibility
    featureLayer.SetLabelVisibility(!featureLayer.IsLabelVisible);
}

/// <summary>
{
  // Note: call within QueuedTask.Run()
  {
    if (!featureLayer.IsLabelVisible)
      //set the label's visibility
      featureLayer.SetLabelVisibility(true);
  }
}