Event:SKILL UPDATE COOLDOWN

Occurs when the player casts a spell.
Arguments:
arg1 - Usually contains the message of what happened (for example: "<playername> casts <spell> on <targetname>", on some spells: "You cast <spellname>", some spells do not give any message at all (like Wave Armor).
Use the arg1 to pick up instant spell casts by parsing it with "You" / <yourname> and <spellame>, perhaps even <targetname> that you want to trigger something in your addon.