// since Go maps never free memory.
const mapReInitializeThreshold = 1000

type userNsPodsManager interface {
	HandlerSupportsUserNamespaces(runtimeHandler string) (bool, error)
	GetPodDir(podUID types.UID) string
	ListPodsFromDisk() ([]types.UID, error)
	GetKubeletMappings() (uint32, uint32, error)
	GetMaxPods() int
}

type UsernsManager struct {
	used    *allocator.AllocationBitmap

			// one here.
			continue
		}

		// Call RemoveAllOneFilesystem for remaining subdirs under the pod directory
		podDir := kl.getPodDir(uid)
		podSubdirs, err := os.ReadDir(podDir)
		if err != nil {
			errorPods++
			klog.ErrorS(err, "Could not read directory", "path", podDir)

	GetPodDNS(pod *v1.Pod) (dnsConfig *runtimeapi.DNSConfig, err error)
	// GetPodCgroupParent returns the CgroupName identifier, and its literal cgroupfs form on the host
	// of a pod.
	GetPodCgroupParent(pod *v1.Pod) string
	GetPodDir(podUID types.UID) string
	GeneratePodHostNameAndDomain(pod *v1.Pod) (hostname string, hostDomain string, err error)
	// GetExtraSupplementalGroupsForPod returns a list of the extra