TRIM considerations when repartitioning a SSD

[Mike Clarke]

FreeBSD 9.3-RELEASE

I may soon need to repartition a SSD which has a zpool on it and was 
wondering what is the best method of ensuring that all blocks get 
marked as no longer in use.

Is gpart sufficiently TRIM aware to be able to just use gpart delete?

If not then I expect I'll need some or all of the following steps in 
order:

     rm -rf <filesystem>
     zfs destroy -r <zfs_filesystem>
     zpool destroy <pool>
     gpart delete -i <index> <geom>

How far down that list would be the best point to start?

-- 
Mike Clarke