code: func go_callback(id C.int, data *C.uchar, len C.int, queue_id C.int) {
  	// TODO: check cast of id
  	payload := &RawPacket{
  		ID:   uint32(id),
  		Data: C.GoBytes(unsafe.Pointer(data), len),
  	}
  
  	dispatch(uint16(queue_id), payload)
  }
docs: //export go_callback