For the cases where configuration interfaces have some sideband signals as well along with regular address and data interfaces, what are recommendations as methodology to edit/modify/extend UVM classes. In RAL system, data flows from Sequences to adapter class via model and uvm_reg class functions. RAL model have write/read tasks which comes with an option of extention field which is of type uvm_object. But seemingly there are no option to pass this field to adapter class as adapter class had fixed structure object as argument in reg2bus/bus2reg tasks. What are recommendation in such cases. workaround in driver VIP or there are some means provided as part of UVM base classes. Applications: IPs attached with crossbar.