code: func (a *Airport) processDepartures() {
  	for {
  		departure, ok := <-a.departureChan
  		if !ok {
  			a.log.Errorf("departure channel closed")
  			return
  		}
  		switch departure.GetChangeType() {
  		case datasync.Put:
  			fl := flight.Info{}
  			if err := departure.GetValue(&fl); err != nil {
  				a.log.Errorf("failed to get value for departure flight: %v", err)
  				continue
  			}
  			fl.Status = flight.Status_departure
  			a.runwayChan <- fl
  		case datasync.Delete:
  			a.log.Debugf("departure %s deleted\n", departure.GetKey())
  		}
  	}
  }
docs: // Wait for departures. Outgoing flights are set to 'departure' and sent to runway