code: func (v *Arrow) native() *C.GtkArrow {
  	if v == nil || v.GObject == nil {
  		return nil
  	}
  	p := unsafe.Pointer(v.GObject)
  	return C.toGtkArrow(p)
  }
docs: /*
   * GtkArrow
   * deprecated since version 3.14
   */
  // native returns a pointer to the underlying GtkButton.