code: func (s *GitScanner) ScanRefs(include, exclude []string, cb GitScannerFoundPointer) error {
  	callback, err := firstGitScannerCallback(cb, s.FoundPointer)
  	if err != nil {
  		return err
  	}
  
  	opts := s.opts(ScanRefsMode)
  	opts.SkipDeletedBlobs = false
  	return scanRefsToChan(s, callback, include, exclude, opts)
  }
docs: // ScanRefs through all commits reachable by refs contained in "include" and
  // not reachable by any refs included in "excluded"