code: func Move(from, to Instance) (err error) {
  	rc, err := from.Get()
  	if err != nil {
  		return
  	}
  	defer rc.Close()
  	err = to.Put(rc)
  	if err != nil {
  		return
  	}
  	from.Delete()
  	return
  }
docs: // Move instance content, deleting the source if it succeeds.