public new Feature CreateRow( 
   RowBuffer featureBuffer
)

public async Task CreatingAFeature()
{
    string message = String.Empty;
    bool creationResult = false;

    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
        using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file\\sdefile.sde"))))
        using (FeatureClass enterpriseFeatureClass = geodatabase.OpenDataset<FeatureClass>("LocalGovernment.GDB.FacilitySite"))
        {
            //var geodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(uri)) for a File GDB
            //
            //var shapeFileConnPath = new FileSystemConnectionPath(uri, FileSystemDatastoreType.Shapefile);
            //var shapefile = new FileSystemDatastore(shapeFileConnPath);
            //var table = shapefile.OpenDataset<Table>(strShapeFileName); for a Shape file

            //declare the callback here. We are not executing it yet
            EditOperation editOperation = new EditOperation();
            editOperation.Callback(context =>
            {
                FeatureClassDefinition facilitySiteDefinition = enterpriseFeatureClass.GetDefinition();
                int facilityIdIndex = facilitySiteDefinition.FindField("FACILITYID");

                using (RowBuffer rowBuffer = enterpriseFeatureClass.CreateRowBuffer())
                {
                    // Either the field index or the field name can be used in the indexer.
                    rowBuffer[facilityIdIndex] = "wMain";
                    rowBuffer["NAME"] = "Griffith Park";
                    rowBuffer["OWNTYPE"] = "Municipal";
                    rowBuffer["FCODE"] = "Park";
                    // Add it to Public Attractions Subtype.
                    rowBuffer[facilitySiteDefinition.GetSubtypeField()] = 820;

                    List<Coordinate2D> newCoordinates = new List<Coordinate2D>
                    {
                            new Coordinate2D(1021570, 1880583),
                            new Coordinate2D(1028730, 1880994),
                            new Coordinate2D(1029718, 1875644),
                            new Coordinate2D(1021405, 1875397)
                        };

                    rowBuffer[facilitySiteDefinition.GetShapeField()] = new PolygonBuilderEx(newCoordinates).ToGeometry();

                    using (Feature feature = enterpriseFeatureClass.CreateRow(rowBuffer))
                    {
                        //To Indicate that the attribute table has to be updated
                        context.Invalidate(feature);
                    }
                }

            }, enterpriseFeatureClass);

            try
            {
                creationResult = editOperation.Execute();
                if (!creationResult) message = editOperation.ErrorMessage;
            }
            catch (GeodatabaseException exObj)
            {
                message = exObj.Message;
            }
        }
    });

    if (!string.IsNullOrEmpty(message))
        MessageBox.Show(message);
}