code: function stringify (headers, options) {
    var result = '';
    if (options) {
      result += 'HTTP/' + options.httpVersion + ' ' +
                options.statusCode + ' ' + status[options.statusCode] +
                '\r\n';
    }
  
    var keys = Object.keys(headers);
    keys.forEach(function (key) {
      if (key === 'set-cookie') {
        headers[key].forEach(function (cookie) {
          result += capitalize.words(key) + ': ' + cookie + '\r\n';
        });
      } else {
        result += capitalize.words(key) + ': ' + headers[key] + '\r\n';
      }
    });
    return result;
  }
docs: Stringify http header properties to form a serialized string.
  @param {json} headers
  A json object with header properties.
  Example:
  {content-type: 'text/html;',
  cache-control: 'no-cache, no-store'}
  
  @param {json} [optional] options
  A json object containing respose details like httpVersion
  and statusCode.
  Example: {httpVersion: '1.1', statusCode: 200}