Function set_kernel_arguments 

pub fn set_kernel_arguments(
    args_to_add: &[&str],
    args_to_remove: &[&str],
) -> ActionSpec

Add and remove kernel arguments. The daemon sends append <arg> and delete <arg> pairs, and the helper writes --append=<arg> and --delete=<arg> itself, so no option reaches rpm-ostree from this argv. With both lists empty the helper runs a bare rpm-ostree kargs, which prints them.