/// <summary>
 /// Stops polling for markers.
 /// </summary>
 public override void StopRetrievingMarkers()
 {
     if (IsRetrievingMarkers)
     {
         base.StopRetrievingMarkers();
         _request.StopPolling();
         IsRetrievingMarkers = false;
     }
 }
 /// <summary>
 /// Stops polling for markers.
 /// </summary>
 public void StopRetrievingMarkers()
 {
     _request.StopPolling();
 }