code: func deflate(data []byte) ([]byte, error) {
  	var buffer bytes.Buffer
  	w := zlib.NewWriter(&buffer)
  	if _, err := w.Write(data); err != nil {
  		return nil, err
  	}
  	if err := w.Close(); err != nil {
  		return nil, err
  	}
  	return buffer.Bytes(), nil
  }
docs: // deflate compresses a string using the DEFLATE format.