code: public Parameters append(String key, String value) {
          if (nameValuePairs == null) {
              nameValuePairs = new ArrayList<NameValuePair>();
          }
          nameValuePairs.add(new BasicNameValuePair(key, value));
          return this;
      }
docs: 追加 from-urlencode参数
  
  @param key
  @param value
  @return