code: func (d *destination) down() {
  	d.active = false
  	log.Infof("%v: %v backend %v down", d.service.vserver, d.service, d)
  
  	ncc := d.service.vserver.ncc
  	if err := ncc.Dial(); err != nil {
  		log.Fatalf("%v: failed to connect to NCC: %v", d.service.vserver, err)
  	}
  	defer ncc.Close()
  	if err := ncc.IPVSDeleteDestination(d.service.ipvsSvc, d.ipvsDst); err != nil {
  		log.Fatalf("%v: failed to delete destination %v: %v", d.service.vserver, d, err)
  	}
  }
docs: // down takes down a destination.