public enum FeatureRendererTarget : System.Enum, System.IComparable, System.IConvertible, System.IFormattable, System.ISpanFormattable  

{
  //The layer must be track aware and spatial
  if (streamLayer.TrackType != TrackType.Spatial)
  {
    // not track aware and spatial
  }
  // Note: call within QueuedTask.Run()
  {
    //Define unique value classes same as we do for current observations
    //or use "CreateRenderer(...)" to assign them automatically
    CIMUniqueValueClass uvcB727Prev = new CIMUniqueValueClass()
    {
      Values = new CIMUniqueValue[] { new CIMUniqueValue() {
      FieldValues = new string[] { "B727" } } },
      Visible = true,
      Label = "Boeing 727",
      Symbol = SymbolFactory.Instance.ConstructPointSymbol(
      CIMColor.CreateRGBColor(255, 0, 0), 4, SimpleMarkerStyle.Hexagon)
      .MakeSymbolReference()
    };

    CIMUniqueValueClass uvcD9Prev = new CIMUniqueValueClass()
    {
      Values = new CIMUniqueValue[] { new CIMUniqueValue() {
      FieldValues = new string[] { "DC9" } } },
      Visible = true,
      Label = "DC 9",
      Symbol = SymbolFactory.Instance.ConstructPointSymbol(
        CIMColor.CreateRGBColor(0, 255, 0), 4, SimpleMarkerStyle.Hexagon)
        .MakeSymbolReference()
    };

    CIMUniqueValueGroup uvGrpPrev = new CIMUniqueValueGroup()
    {
      Classes = new CIMUniqueValueClass[] { uvcB727Prev, uvcD9Prev }
    };

    var UVrndr = new CIMUniqueValueRenderer()
    {
      Fields = new string[] { "ACTYPE" },
      Groups = new CIMUniqueValueGroup[] { uvGrpPrev },
      UseDefaultSymbol = true,
      DefaultLabel = "Others",
      DefaultSymbol = SymbolFactory.Instance.ConstructPointSymbol(
        CIMColor.CreateRGBColor(185, 185, 185), 4, SimpleMarkerStyle.Hexagon)
        .MakeSymbolReference()
    };

    streamLayer.SetRenderer(UVrndr, FeatureRendererTarget.PreviousObservations);
  }
}

{
  // Note: call within QueuedTask.Run()
  {
    //The layer must be track aware and spatial
    if (streamLayer.TrackType != TrackType.Spatial)
    {
      // not track aware and spatial
    }

    //Note: only a simple renderer with solid line symbol is supported for track 
    //line renderer
    var trackRenderer = new SimpleRendererDefinition()
    {
      SymbolTemplate = SymbolFactory.Instance.ConstructLineSymbol(
          ColorFactory.Instance.BlueRGB, 2, SimpleLineStyle.Solid)
            .MakeSymbolReference()
    };
    streamLayer.SetRenderer(
         streamLayer.CreateRenderer(trackRenderer),
           FeatureRendererTarget.TrackLines);
  }
}

{
  //The layer must be track aware and spatial
  if (streamLayer.TrackType != TrackType.Spatial)
  {
    // not track aware and spatial
  }
  // Note: call within QueuedTask.Run()
  {
    var prev_renderer = streamLayer.GetRenderer(
    FeatureRendererTarget.PreviousObservations);
  }
}

{
  //The layer must be track aware and spatial
  if (streamLayer.TrackType != TrackType.Spatial)
  {

  }

  // Note: call within QueuedTask.Run()
  {
    var track_renderer = streamLayer.GetRenderer(
      FeatureRendererTarget.TrackLines);
  }
}