code: func parseMetaRow(v []byte) (m meta, err error) {
  	row := v
  	sp := bytes.IndexByte(v, ' ')
  	if sp < 1 || sp == len(v)-1 {
  		return meta{}, fmt.Errorf("invalid metarow %q", v)
  	}
  	m.exists = true
  	size, err := strutil.ParseUintBytes(v[:sp], 10, 32)
  	if err != nil {
  		return meta{}, fmt.Errorf("invalid metarow size %q", v)
  	}
  	m.size = uint32(size)
  	v = v[sp+1:]
  
  	// remains: "<big-blobref> <big-offset>"
  	if bytes.Count(v, singleSpace) != 1 {
  		return meta{}, fmt.Errorf("invalid metarow %q: wrong number of spaces", row)
  	}
  	sp = bytes.IndexByte(v, ' ')
  	largeRef, ok := blob.ParseBytes(v[:sp])
  	if !ok {
  		return meta{}, fmt.Errorf("invalid metarow %q: bad blobref %q", row, v[:sp])
  	}
  	m.largeRef = largeRef
  	off, err := strutil.ParseUintBytes(v[sp+1:], 10, 32)
  	if err != nil {
  		return meta{}, fmt.Errorf("invalid metarow %q: bad offset: %v", row, err)
  	}
  	m.largeOff = uint32(off)
  	return m, nil
  }
docs: // parses:
  // "<size_u32> <big-blobref> <big-offset>"