code: func getIPTablesRestoreWaitFlag(exec utilexec.Interface, protocol Protocol) []string {
  	vstring, err := getIPTablesRestoreVersionString(exec, protocol)
  	if err != nil || vstring == "" {
  		klog.V(3).Infof("couldn't get iptables-restore version; assuming it doesn't support --wait")
  		return nil
  	}
  	if _, err := utilversion.ParseGeneric(vstring); err != nil {
  		klog.V(3).Infof("couldn't parse iptables-restore version; assuming it doesn't support --wait")
  		return nil
  	}
  
  	return []string{WaitString, WaitSecondsValue}
  }
docs: // Checks if iptables-restore has a "wait" flag
  // --wait support landed in v1.6.1+ right before --version support, so
  // any version of iptables-restore that supports --version will also
  // support --wait