Eric Blake writes:
> Implement the new type_null() callback for the qmp input and
> output visitors. While we don't yet have a use for this in QAPI
> input (the generator will need some tweaks first), one usage
> is already envisioned: when changing blockdev parameters, it
> would be nice to have
Implement the new type_null() callback for the qmp input and
output visitors. While we don't yet have a use for this in QAPI
input (the generator will need some tweaks first), one usage
is already envisioned: when changing blockdev parameters, it
would be nice to have a difference between leaving a
