on average) and rapid updates to pod configuration should take effect sooner.
  
  A new metric `kubelet_known_pods` has been added at ALPHA stability to report the number of pods a Kubelet is tracking in a number of internal states.  Operators may use the metrics to track an excess of pods in the orphaned state that may not be completing. ([#113145](https://github.com/kubernetes/kubernetes/pull/113145), [@smarterclayton](https://github.com/smarterclayton)) [SIG API Machinery, Auth, Cloud...

* Switch JSON marshal/unmarshal to json-iterator library.  Performance should be close to previous with no generated code. ([#48287](https://github.com/kubernetes/kubernetes/pull/48287), [@thockin](https://github.com/thockin))

- 'Priority and Fairness has introduced a new feature called _borrowing_ that allows an API priority level
  to borrow a number of seats from other priority level(s). As a cluster operator, you can enable borrowing
  for a certain priority level configuration object via the two newly introduced fields `lendablePercent`, and