code: public OpenStackRequest<R> queryString(String queryString) {
          if (queryString != null) {
              String[] params = queryString.split("&");
              for (String param : params) {
                  String[] s = param.split("=");
                  if (s[0] != null && s[1] != null) {
                      queryParam(s[0], s[1]);
                  }
              }
          }
          return this;
      }
docs: This method will parse the query string which is a collection of name value pairs and put then in queryParam hash
  map
  
  @param queryString
  The query string to be parsed
  @return The request object