internal static extern void iaxc_set_event_callback(iaxc_event_callback_t func);
internal static extern void iaxc_set_event_callback(iaxc_event_callback_t func);
internal static extern void iaxc_set_event_callback(iaxc_event_callback_t func);
internal static extern void iaxc_set_event_callback(iaxc_event_callback_t func);