SET_ITEM
backend = SET_ITEM(pci_vtscsi_backend_set, 0);
printf("item(foo, 0): %s\n", SET_ITEM(foo, 0)->buf);
printf("item(foo, 1): %s\n", SET_ITEM(foo, 1)->buf);
printf("item(foo, 2): %s\n", SET_ITEM(foo, 2)->buf);