code: func (id ID) ShortString() string {
  	pid := id.Pretty()
  	if len(pid) <= 10 {
  		return fmt.Sprintf("<peer.ID %s>", pid)
  	}
  	return fmt.Sprintf("<peer.ID %s*%s>", pid[:2], pid[len(pid)-6:])
  }
docs: // String prints out the peer.
  //
  // TODO(brian): ensure correctness at ID generation and
  // enforce this by only exposing functions that generate
  // IDs safely. Then any peer.ID type found in the
  // codebase is known to be correct.