public RowToken Create( 
   Layer layer,
   Geometry geometry
)

var createFeatures = new EditOperation();
createFeatures.Name = "Create Features";
//Create a feature with a polygon
var token = createFeatures.Create(featureLayer, polygon);
if (createFeatures.IsSucceeded)
{
  // token.ObjectID wll be populated with the objectID of the created feature after Execute has been successful
}
//Do a create features and set attributes
var attributes = new Dictionary<string, object>();
attributes.Add("SHAPE", polygon);
attributes.Add("NAME", "Corner Market");
attributes.Add("SIZE", 1200.5);
attributes.Add("DESCRIPTION", "Corner Market");

createFeatures.Create(featureLayer, attributes);

//Create features using the current template
//Must be within a MapTool
createFeatures.Create(this.CurrentTemplate, polygon);

//Execute to execute the operation
//Must be called within QueuedTask.Run
createFeatures.Execute();

//or use async flavor
//await createFeatures.ExecuteAsync();

{
  var duplicateFeatures = new EditOperation();
  duplicateFeatures.Name = "Duplicate Features";

  //Duplicate with an X and Y offset of 500 map units
  //At 2.x duplicateFeatures.Duplicate(featureLayer, oid, 500.0, 500.0, 0.0);

  //Execute to execute the operation
  //Must be called within QueuedTask.Run
  var insp2 = new Inspector();
  insp2.Load(featureLayer, oid);
  var geom = insp2["SHAPE"] as Geometry;

  var rtoken = duplicateFeatures.Create(insp2.MapMember, insp2.ToDictionary(a => a.FieldName, a => a.CurrentValue));
  if (duplicateFeatures.Execute())
  {
    var modifyOp = duplicateFeatures.CreateChainedOperation();
    modifyOp.Modify(featureLayer, (long)rtoken.ObjectID, GeometryEngine.Instance.Move(geom, 500.0, 500.0));
    modifyOp.Execute();
  }

}