code: func (iter *Iterator) CurrentBuffer() string {
  	peekStart := iter.head - 10
  	if peekStart < 0 {
  		peekStart = 0
  	}
  	return fmt.Sprintf("parsing #%v byte, around ...|%s|..., whole buffer ...|%s|...", iter.head,
  		string(iter.buf[peekStart:iter.head]), string(iter.buf[0:iter.tail]))
  }
docs: // CurrentBuffer gets current buffer as string for debugging purpose