code: func (resp *Response) WriteDeflateLevel(w *bufio.Writer, level int) error {
  	if err := resp.deflateBody(level); err != nil {
  		return err
  	}
  	return resp.Write(w)
  }
docs: // WriteDeflateLevel writes response with deflated body to w.
  //
  // Level is the desired compression level:
  //
  //     * CompressNoCompression
  //     * CompressBestSpeed
  //     * CompressBestCompression
  //     * CompressDefaultCompression
  //     * CompressHuffmanOnly
  //
  // The method deflates response body and sets 'Content-Encoding: deflate'
  // header before writing response to w.
  //
  // WriteDeflateLevel doesn't flush response to w for performance reasons.