public void Delete(IEnumerable <IRow> rows)
 {
     // Could probably do bulk updates with partition and bulk operation
     foreach (var row in rows)
     {
         var id = string.Concat(_context.OutputFields.Where(f => f.PrimaryKey).Select(f => row[f]));
         _client.Update <VoidResponse>(_index, _type, id, row.ToExpandoObject(_fields));
     }
 }