nsd-control parser update, zone transfer status

[pettai]

This update parses some additional fields/state that surface during (manual) zone transfers

[kellyjonbrazil]

Looks good - do we need to update the schema with the new fields?

[pettai]

Ah, I started on that at first, but since it it's either wait: string or notified-serial: string + transfer: string, I backed it, and then I forgot about that while doing the actual update + tests. is there a way of describing optional / shifting fields? or do we simply copy-n-paste with modifications?
I noticed there are two more ("optional") fields missing from earlier additions too...

[kellyjonbrazil]

I just add all of the possible fields. I try not to have fields with multiple possible types, but if that’s impossible to avoid I just add a comment to describe the behavior. If it’s more than a few words I do it with a footnote so it doesn’t pass 80 chars in the row.