public bool UseDefaultSymbol {get; set;}

return QueuedTask.Run(() =>
{
  //The goal is to construct the CIMUniqueValueRenderer which will be applied to the feature layer.
  // To do this, the following are the objects we need to set the renderer up with the fields and symbols.
  // As a reference, this is the USCities dataset. Snippet will create a unique value renderer that applies 
  // specific symbols to all the cities in California and Alabama.  The rest of the cities will use a default symbol.

  // First create a "CIMUniqueValueClass" for the cities in Alabama.
  List<CIMUniqueValue> listUniqueValuesAlabama = new List<CIMUniqueValue> { new CIMUniqueValue { FieldValues = new string[] { "Alabama" } } };
  CIMUniqueValueClass alabamaUniqueValueClass = new CIMUniqueValueClass
  {
    Editable = true,
    Label = "Alabama",
    Patch = PatchShape.Default,
    Symbol = SymbolFactory.Instance.ConstructPointSymbol(ColorFactory.Instance.RedRGB).MakeSymbolReference(),
    Visible = true,
    Values = listUniqueValuesAlabama.ToArray()

  };
  // Create a "CIMUniqueValueClass" for the cities in California.
  List<CIMUniqueValue> listUniqueValuescalifornia = new List<CIMUniqueValue> { new CIMUniqueValue { FieldValues = new string[] { "California" } } };
  CIMUniqueValueClass californiaUniqueValueClass = new CIMUniqueValueClass
  {
    Editable = true,
    Label = "California",
    Patch = PatchShape.Default,
    Symbol = SymbolFactory.Instance.ConstructPointSymbol(ColorFactory.Instance.BlueRGB).MakeSymbolReference(),
    Visible = true,
    Values = listUniqueValuescalifornia.ToArray()
  };
  //Create a list of the above two CIMUniqueValueClasses
  List<CIMUniqueValueClass> listUniqueValueClasses = new List<CIMUniqueValueClass>
    {
                  alabamaUniqueValueClass, californiaUniqueValueClass
    };
  //Create a list of CIMUniqueValueGroup
  CIMUniqueValueGroup uvg = new CIMUniqueValueGroup
  {
    Classes = listUniqueValueClasses.ToArray(),
  };
  List<CIMUniqueValueGroup> listUniqueValueGroups = new List<CIMUniqueValueGroup> { uvg };
  //Create the CIMUniqueValueRenderer
  CIMUniqueValueRenderer uvr = new CIMUniqueValueRenderer
  {
    UseDefaultSymbol = true,
    DefaultLabel = "all other values",
    DefaultSymbol = SymbolFactory.Instance.ConstructPointSymbol(ColorFactory.Instance.GreyRGB).MakeSymbolReference(),
    Groups = listUniqueValueGroups.ToArray(),
    Fields = new string[] { "STATE_NAME" }
  };
  //Set the feature layer's renderer.
  featureLayer.SetRenderer(uvr);
});

var url = @"https://geoeventsample1.esri.com:6443/arcgis/rest/services/AirportTraffics/StreamServer";
var uri = new Uri(url, UriKind.Absolute);
//Must be on QueuedTask!

var createParams = new FeatureLayerCreationParams(uri)
{
  IsVisible = false
};
var streamLayer = LayerFactory.Instance.CreateLayer<StreamLayer>(
                    createParams, map);
//Define the unique values by hand
var uvr = new CIMUniqueValueRenderer()
{
  Fields = new string[] { "ACTYPE" },
  UseDefaultSymbol = true,
  DefaultLabel = "Others",
  DefaultSymbol = SymbolFactory.Instance.ConstructPointSymbol(
              CIMColor.CreateRGBColor(185, 185, 185), 8, SimpleMarkerStyle.Hexagon).MakeSymbolReference()
};

var classes = new List<CIMUniqueValueClass>();
//add in classes - one for ACTYPE of 727, one for DC 9
classes.Add(
  new CIMUniqueValueClass() {
        Values = new CIMUniqueValue[] {
              new CIMUniqueValue() { FieldValues = new string[] { "B727" } } },
        Visible = true,
        Label = "Boeing 727",
        Symbol = SymbolFactory.Instance.ConstructPointSymbol(
              ColorFactory.Instance.RedRGB, 10, SimpleMarkerStyle.Hexagon).MakeSymbolReference()
});
classes.Add(
  new CIMUniqueValueClass()
  {
    Values = new CIMUniqueValue[] {
              new CIMUniqueValue() { FieldValues = new string[] { "DC9" } } },
    Visible = true,
    Label = "DC 9",
    Symbol = SymbolFactory.Instance.ConstructPointSymbol(
              ColorFactory.Instance.GreenRGB, 10, SimpleMarkerStyle.Hexagon).MakeSymbolReference()
  });
//add the classes to a group
var groups = new List<CIMUniqueValueGroup>()
{
  new CIMUniqueValueGroup() {
     Classes = classes.ToArray()
  }
};
//add the groups to the renderer
uvr.Groups = groups.ToArray();
//Apply the renderer (for current observations)
streamLayer.SetRenderer(uvr);
streamLayer.SetVisibility(true);//turn on the layer

var url = @"https://geoeventsample1.esri.com:6443/arcgis/rest/services/AirportTraffics/StreamServer";
var uri = new Uri(url, UriKind.Absolute);
//Must be on QueuedTask!

var createParams = new FeatureLayerCreationParams(uri)
{
  IsVisible = false
};
var streamLayer = LayerFactory.Instance.CreateLayer<StreamLayer>(
                    createParams, map);
//Define the unique values by hand
var uvr = new CIMUniqueValueRenderer()
{
  Fields = new string[] { "ACTYPE" },
  UseDefaultSymbol = true,
  DefaultLabel = "Others",
  DefaultSymbol = SymbolFactory.Instance.ConstructPointSymbol(
              CIMColor.CreateRGBColor(185, 185, 185), 8, SimpleMarkerStyle.Hexagon).MakeSymbolReference()
};

var classes = new List<CIMUniqueValueClass>();
//add in classes - one for ACTYPE of 727, one for DC 9
classes.Add(
  new CIMUniqueValueClass() {
        Values = new CIMUniqueValue[] {
              new CIMUniqueValue() { FieldValues = new string[] { "B727" } } },
        Visible = true,
        Label = "Boeing 727",
        Symbol = SymbolFactory.Instance.ConstructPointSymbol(
              ColorFactory.Instance.RedRGB, 10, SimpleMarkerStyle.Hexagon).MakeSymbolReference()
});
classes.Add(
  new CIMUniqueValueClass()
  {
    Values = new CIMUniqueValue[] {
              new CIMUniqueValue() { FieldValues = new string[] { "DC9" } } },
    Visible = true,
    Label = "DC 9",
    Symbol = SymbolFactory.Instance.ConstructPointSymbol(
              ColorFactory.Instance.GreenRGB, 10, SimpleMarkerStyle.Hexagon).MakeSymbolReference()
  });
//add the classes to a group
var groups = new List<CIMUniqueValueGroup>()
{
  new CIMUniqueValueGroup() {
     Classes = classes.ToArray()
  }
};
//add the groups to the renderer
uvr.Groups = groups.ToArray();
//Apply the renderer (for current observations)
streamLayer.SetRenderer(uvr);
streamLayer.SetVisibility(true);//turn on the layer