code: func (s *TranslateFile) monitorPrimaryStoreEvents() {
  	// Keep handling events until the store closes.
  	for {
  		select {
  		case <-s.closing:
  			return
  		case ev := <-s.primaryStoreEvents:
  			if err := s.handlePrimaryStoreEvent(ev); err != nil {
  				s.logger.Printf("handle primary store event")
  			}
  		}
  	}
  }
docs: // monitorPrimaryStoreEvents is executed in a separate goroutine and listens for changes
  // to the primary store assignment.