anchor.diff:     * of parameters.
      */
     async.Future<HttpResponse> jsonp(String url, {
  -    String data,
  +    dynamic data,
       Map<String, dynamic> params,
       Map<String, String> headers,
       bool withCredentials: false,
  
positive.code:     });
  
      var serverRequest = (HttpResponseConfig config) {
        assert(config.data == null || config.data is String || config.data is dom.File);
  
        // Strip content-type if data is undefined
        if (config.data == null) {
          new List.from(headers.keys)
  
negative.code:    * of parameters.
     */
    async.Future<HttpResponse> get(String url, {
      Map<String, dynamic> params,
      Map<String, String> headers,
      bool withCredentials: false,
  