fun <T : Bus<T>> T.audio(audioUrl: String, vararg quickReplies: QuickReply): AttachmentMessage (source)fun <T : Bus<T>> T.audio(audioUrl: String, quickReplies: List<QuickReply>): AttachmentMessage (source)
Creates an audio file as attachment (https://developers.facebook.com/docs/messenger-platform/reference/send-api/#attachment).