Fired when a battle pet gains experience during a pet battle.
PET_BATTLE_XP_CHANGED: owner, petIndex, xpChange
- number - team to which the pet belongs, 1 for the player's team, 2 for the opponent.
- number - pet index within the team.
- number - amount of XP gained.
- The PetJournal and PetBattles APIs still return the old level/experience information for the pet when this event fires.
Patch 5.0.4 (2012-08-28): Added.