public bool IsTrackAware {get;}

{
  var trackAwareLayers = MapView.Active.Map.GetLayersAsFlattenedList()
                             .OfType<StreamLayer>().Where(sl => sl.IsTrackAware)?.ToList();
}

{
  if (streamLayer.IsTrackAware)
  {
    var trackField = streamLayer.TrackIdFieldName;
    //TODO use the field name
  }
}

{
  // Note: call within QueuedTask.Run()
  {
    //Set Expiration Method and Max Expiration Count
    if (streamLayer.GetExpirationMethod() != FeatureExpirationMethod.MaximumFeatureCount)
      streamLayer.SetExpirationMethod(FeatureExpirationMethod.MaximumFeatureCount);
    streamLayer.SetExpirationMaxCount(15);
    //FYI
    if (streamLayer.IsTrackAware)
    {
      //MaxCount is per track! otherwise for the entire layer
    }
  }
}