code: function isNetworkIssue(error) {
      // We don't want to retry when a HTTP error occurred.
      return !(error instanceof errors.HttpError) &&
        !(error instanceof errors.ParserError) &&
        !(error instanceof errors.AbortError);
    }
docs: Determine whether the error is due to a network problem. We do not perform diagnosis on errors like an HTTP status code of 400 because errors like these are an indication that the application was not queried properly rather than a problem with the server being inaccessible or a network issue. So we need to distinguish network issues from the rest.