anchor.diff:  
     /**
      * Returns the response headers.
  +   *
  +   * The response headers can be modified until the response body is
  +   * written to or closed. After that they become immutable.
      */
     HttpHeaders get headers;
   
  
positive.code:    * the official HTTP status codes use the fields from
     * [HttpStatus]. If no status code is explicitly set the default
     * value [HttpStatus.OK] is used.
     */
    int statusCode;
  
    /**
     * Gets and sets the reason phrase. If no reason phrase is explicitly
     * set a default reason phrase is provided.
     */
    String reasonPhrase;
  
  
negative.code:   int contentLength;
  
    /**
     * Returns the client request headers.
     *
     * The client request headers can be modified until the client
     * request body is written to or closed. After that they become
     * immutable.
     */
    HttpHeaders get headers;
  
  