||Returns the client ID of the client added to or removed from the room, or whose attribute changed.
||Returns an object containing information about a changed client or room attribute. The object's properties are:
attrName - the name of the attribute
attrVal - the new value of the attribute
fqRoomID - the scope of the changed client attribute (does not apply to room attributes)
||Returns the number of unique clients now in this room.
||Returns the status of the operation to which this event pertains (either joining or leaving the room).