data.go
func (d *Data) Close() error {
	if d.dh == nil {
		return nil
	}
	if d.cbc > 0 {
		callbackDelete(d.cbc)
	}
	_, err := C.gpgme_data_release(d.dh)
	d.dh = nil
	return err
}
func (d *Data) Close() error {
	if d.dh == nil {
		return nil
	}
	if d.cbc > 0 {
		callbackDelete(d.cbc)
	}
	_, err := C.gpgme_data_release(d.dh)
	d.dh = nil
	return err
}
// Close releases any resources associated with the data buffer