function(_,_,message,_,_,source,_,_,dest,_,_,_,_,spell,_,_)
    local dot = "Shadow Word: Pain"

    -- Only care about "dot" if it's cast by the player.
    if (UnitIsUnit(source or "", "player") and spell == dot) then
        -- Setup global variables incase they aren't already done.
        WA_DOTS = WA_DOTS or {}
        WA_DOTS[dot] = WA_DOTS[dot] or {}
        -- Aura applied, record stats
        if (message == "SPELL_AURA_APPLIED") or (message == "SPELL_AURA_REFRESH") then
            local stats = {}
            stats.haste = UnitSpellHaste("player") or 0
            WA_DOTS[dot][dest] = stats
            return true
        end
        -- Aura removed, stop tracking it.
        if (message == "SPELL_AURA_REMOVED") then
            WA_DOTS[dot][dest] = nil
            table.remove(WA_DOTS[dot], dest)
            return false
        end
    end

    return false
end