Attempts to exit the World of Warcraft client. Results vary based on current conditions:

• If the player is in combat or under other temporary restrictions (e.g. falling), fires the UI_ERROR_MESSAGE event with a message indicating the player cannot log out at the moment.
• If the player is not in an inn, major city, or other "rest" area (i.e. IsResting() returns nil), fires the PLAYER_QUITING event, causing the default UI to show a countdown, quitting WoW after a period of time if not canceled.
• If the player is in a "rest" area, quits the game immediately.