code: private void fireConnectionError(SQLException e) {
      Code code = Code.UNKNOWN;
      if (e instanceof CloudSpannerSQLException) {
        code = ((CloudSpannerSQLException) e).getCode();
      }
      if (!isFatalState(code)) {
        return;
      }
      fireConnectionFatalError(e);
    }
docs: Fires a connection error event, but only if we think the exception is fatal.
  
  @param e the SQLException to consider