code: func (s *ObjectScanner) Scan(oid string) bool {
  	if err := s.reset(); err != nil {
  		s.err = err
  		return false
  	}
  
  	obj, err := s.scan(oid)
  	s.object = obj
  
  	if err != nil {
  		if err != io.EOF {
  			s.err = err
  		}
  		return false
  	}
  	return true
  }
docs: // Scan scans for a particular object given by the "oid" parameter. Once the
  // scan is complete, the Contents(), Sha1(), Size() and Type() functions may be
  // called and will return data corresponding to the given OID.
  //
  // Scan() returns whether the scan was successful, or in other words, whether or
  // not the scanner can continue to progress.