code: func (e *LoggingErrorGroup) Finalize() (err error) {
  	if e.failed > 0 {
  		err = ErrorGroupError.New("%s: %d of %d failed.", e.name, e.failed,
  			e.total)
  	}
  	e.total = 0
  	e.failed = 0
  	return err
  }
docs: // Finalize returns no error if no failures were observed, otherwise it will
  // return an ErrorGroupError with statistics about the observed errors.