public CIMSymbolReference SymbolTemplate {get; set;}

var url = @"https://geoeventsample1.esri.com:6443/arcgis/rest/services/LABus/StreamServer";
var uri = new Uri(url, UriKind.Absolute);
//Must be on QueuedTask!
var createParams = new FeatureLayerCreationParams(uri)
{
  RendererDefinition = new SimpleRendererDefinition()
  {
    SymbolTemplate = SymbolFactory.Instance.ConstructPointSymbol(
                        ColorFactory.Instance.BlueRGB,
                        12,
                 SimpleMarkerStyle.Pushpin).MakeSymbolReference()
  }
};
var streamLayer = LayerFactory.Instance.CreateLayer<StreamLayer>(
                    createParams, map);