[WeakAura] Track total uptime of Renewing Mist for entire encounter

[Gahage]

Much like you see in WoWAnalyzer for Renewing Mist uptime, I'd like to track this in-game.

Skada almost does it, in that it'll track how long the buff is up on individual players, but I'd like to track total uptime for an entire raid or group (per encounter)

Put another way, I want to track the total time ReM is OFF cooldown and invert that for total % uptime.

[Will]

Warcraft logs should allow this, saving the need to use an add-on.