protected override DataViewRowCursor GetRowCursorCore(IEnumerable <DataViewSchema.Column> columnsNeeded, Random rand = null)
 {
     Host.AssertValue(_pipedTransform, "_pipedTransform");
     return(_pipedTransform.GetRowCursor(columnsNeeded, rand));
 }
 protected override RowCursor GetRowCursorCore(Func <int, bool> needCol, Random rand = null)
 {
     Host.AssertValue(_pipedTransform, "_pipedTransform");
     return(_pipedTransform.GetRowCursor(needCol, rand));
 }