docs: private int getIntHeaderValue(Response response, String key) throws GitLabApiException {
  
          String value = getHeaderValue(response, key);
          if (value == null) {
              return -1;
          }
  
          try {
              return (Integer.parseInt(value));
          } catch (NumberFormatException nfe) {
              throw new GitLabApiException("Invalid '" + key + "' header value (" + value + ") from server");
          }
      }