code: func (c *NotifierKafka) Stop() {
  	// closes notifications and messages channels, amongst others
  	close(c.stopConsuming)
  	c.producer.Close()
  
  	go func() {
  		c.wg.Wait()
  		close(c.StopChan)
  	}()
  }
docs: // Stop will initiate a graceful stop of the Consumer (permanent)
  //
  // NOTE: receive on StopChan to block until this process completes