clone method
Implementation
void clone(TrDto? trDto, {FieldData? fieldData, int? table_id}) {
if(trDto==null && table_id==null) throw ArgumentError("table_id must be passed when TrDto is null");
if (trDto == null) trDto = TrDto.wee(table_id!);
sep(trDto.ts, trDto.operation, trDto.user_id, trDto.user_ts, trDto.comment,
trDto.crc, trDto.table_id,
fieldData: fieldData);
}