public int ValuesLimit {get; set;}

var uvrDef = new UniqueValueRendererDefinition()
{
  ValueFields = new List<string> { "ACTYPE" },
  SymbolTemplate = SymbolFactory.Instance.ConstructPointSymbol(
    ColorFactory.Instance.RedRGB, 10, SimpleMarkerStyle.Hexagon)
      .MakeSymbolReference(),
  ValuesLimit = 5
};
//Note: CreateRenderer can only create value classes based on
//the current events it has received
streamLayer.SetRenderer(streamLayer.CreateRenderer(uvrDef));