code: func RunningWithRootlessKit() bool {
  	runningWithRootlessKitOnce.Do(func() {
  		u := os.Getenv("ROOTLESSKIT_STATE_DIR")
  		runningWithRootlessKit = u != ""
  	})
  	return runningWithRootlessKit
  }
docs: // RunningWithRootlessKit returns true if running under RootlessKit namespaces.