open fun on(event: String, listener: (event: Event, index: Number) -> Unit): Notificationopen fun on(event: String, listener: (event: Event) -> Unit): Notificationopen fun on(event: String, listener: (event: Event) -> Unit): Notificationopen fun on(event: String, listener: (event: Event, reply: String) -> Unit): Notificationopen fun on(event: String, listener: (event: Event) -> Unit): Notification