[Swan-dev] add_time

[D. Hugh Redelmeier]

What is add_time?  It seems to be added in 
1913dd115696793d8dc5d6b6fd3f8238408fc1d1
(last august)

See also a8de85564b4030e496a400ca276af9a7158cd69d

I don't see any documentation.

It seems to derived from netlink (a paragon of documentation)
	rsp.info.curlft.add_time
	where rsp.info is a struct xfrm_usersa

What makes me most suspicious is that it is a uint64_t.  I bet it is some 
kind of time and it should be represented in Pluto in one of its time 
types, not as a raw number.