docs: public String getParametersToString(String prefix) {
          final StringBuilder sb = new StringBuilder();
          getParameters().forEach((k, v) -> {
              if (sb.length() > 0) sb.append('&');
              try {
                  sb.append(k).append('=').append(URLEncoder.encode(v, "UTF-8"));
              } catch (IOException ex) {
                  throw new RuntimeException(ex);
              }
          });
          return (sb.length() > 0 && prefix != null) ? (prefix + sb) : sb.toString();
      }