how can I find out which md device I just used ? (mdconfig)

[user]

mdconfig will use the next available md device, as long as you do not
specify a particular device on the command line with the -u switch.

Which is great.

However, in a script, the very next thing I want to do is mount that
mdconfig'd vnode filesystem.  But I do not know which md device mdconfig
just used.

I do not see any way in the mdconfig man page to get mdconfig to output
what device it is using when it is invoked ...

So ... assuming I am running mdconfig, followed by mount, in a shell
script ... and I do not specify a device becuase i do not know what
devices are available (beacuse I am running it automated) ... how can I
find out (any suggestions appreciated) what md device just got used so I
can mount it ?

I consiudered running `mdconfig -l` before and after the mdconfig, and
choosing the one that shows up as new, but that is not elegant and is
vulnerable to a race condition.

THanks.