public class FeatureLayerCreationParams : LayerCreationParams 

var flyrCreatnParam = new FeatureLayerCreationParams(new Uri(@"c:\data\world.gdb\cities"))
{
  Name = "World Cities",
  IsVisible = false,
  MinimumScale = 1000000,
  MaximumScale = 5000,
  // At 2.x - DefinitionFilter = new CIMDefinitionFilter()
  //{
  //  DefinitionExpression = "Population > 100000",
  //  Name = "More than 100k"
  //},
  DefinitionQuery = new DefinitionQuery(whereClause: "Population > 100000", name: "More than 100k"),
  RendererDefinition = new SimpleRendererDefinition()
  {
    SymbolTemplate = SymbolFactory.Instance.ConstructPointSymbol(
      CIMColor.CreateRGBColor(255, 0, 0), 8, SimpleMarkerStyle.Hexagon).MakeSymbolReference()
  }
};

var featureLayer = LayerFactory.Instance.CreateLayer<FeatureLayer>(
  flyrCreatnParam, map);