docs: public static String @Nullable [] getMultiple(@NotNull ServletRequest request, @NotNull String param) {
      String[] values = request.getParameterValues(param);
      if (values == null) {
        return null;
      }
      // convert encoding to UTF-8 if not form encoding parameter is set
      if (!hasFormEncodingParam(request)) {
        String[] convertedValues = new String[values.length];
        for (int i = 0; i < values.length; i++) {
          if (values[i] != null) {
            convertedValues[i] = convertISO88591toUTF8(values[i]);
          }
        }
        return convertedValues;
      }
      else {
        return values;
      }
    }