This are to the existing sd_varlink_call_and_upgrade() what sd_varlink_callb() and sd_varlink_callbo() are to sd_varlink_call(): they put together an object on the fly, via the usual JSON builder logic.
This are to the existing sd_varlink_call_and_upgrade() what sd_varlink_callb() and sd_varlink_callbo() are to sd_varlink_call(): they put together an object on the fly, via the usual JSON builder logic.