NAME
    libevent - For easier event handling.

FUNCTIONS
    SetEventTranslator(event_name : string, [callback : function]) : nil or function
        Set external event translator. Pass nil to unregister it.
        Return the old event translator.
    
    AddEventListener(EventName : string, CallbackFunction : function) : number
        Add event listener. Return event listener id.

    RemoveEventListener(ListenerID : number) : boolean
        Remove event listener. Only listener id is required.

    WaitEventEx(...) : Event
        Equivalent to event.pull(...), but return event package.

    WaitEvent([timeout : number],[event name : string]) : Event
    WaitEvent([event name : string],[timeout : number]) : Event -- Deprecated
        Simpler waiting event.

    WaitMultipleEvent(...) : Event
        Equivalent to event.pullMultiple(...), but return event package.

    PushEvent(EventName : string,...)
        Equivalent to event.push(EventName,...)

    AddTimer(Interval : number, CallbackFunction : function, Times : number) : number
        Equivalent to event.timer(Interval,CallbackFunction,Times). Times will be math.huge if <0.
    
    RemoveTimer(TimerID : number) : boolean
        Equivalent to event.cancel(TimerID)

    CreateEventBus() : EventBus
        Create a event bus. The event bus works like a FIFO queue.
    
    EventBusListen(t : EventBus, event_name : string, checkfn : function)
    EventBus:listen(event_name : string, checkfn : function)
        Listen a event. All listened events will be automatically added to event bus.
        If checkfn presents, it will be called before adding events. If it returns true, then event will be added.

    EventBus:next([wait_second : number],[wait_ratio : number])
        Get an event from event bus. By default, EventBus:next() will wait until an listened event happens.
    
    EventBus:close()
        Clean up internal buffer and listeners.
        The programmer is responsible for calling this method. (because OC does not support __gc meta-method.)