forwarding a packet, that creates state, until
pfsync(4) peer acks state addition (or 10 msec
timeout passes).
This is needed for active-active CARP configurations,
which are poorly supported in FreeBSD and arguably
a good idea at all.
Unfortunately by the time of import this feature in
OpenBSD was turned on, and did not have a switch to
turn it off. This leaked to FreeBSD.
This change make it possible to turn this feature
off via ioctl() and turns it off by default.
Obtained from: OpenBSD
4a817f8ca2