anchor.diff:     * automatically follow redirects. The default is [:true:].
      *
      * Automatic redirect will only happen for "GET" and "HEAD" requests
  -   * and only for the status codes [:HttpHeaders.MOVED_PERMANENTLY:]
  +   * and only for the status codes [:HttpStatus.MOVED_PERMANENTLY:]
      * (301), [:HttpStatus.FOUND:] (302),
      * [:HttpStatus.MOVED_TEMPORARILY:] (302, alias for
      * [:HttpStatus.FOUND:]), [:HttpStatus.SEE_OTHER:] (303) and
  
positive.code:    */
    bool autoUncompress;
  
    /**
     * Set and get the default value of the `User-Agent` header for all requests
     * generated by this [HttpClient]. The default value is
     * `Dart/<version> (dart:io)`.
     *
     * If the userAgent is set to `null`, no default `User-Agent` header will be
     * added to each request.
     */
    String userAgent;
  
    factory HttpClient({SecurityContext context}) {
  
negative.code:   /**
     * Gets the map of parameters.
     *
     * This map cannot be modified. Invoking any operation which would
     * modify the map will throw [UnsupportedError].
     */
    Map<String, String> get parameters;
  