- Client-go: Optimized leaders renewing leases by updating leader lock optimistically without getting the record from the API server first. Also, a new metric `leader_election_slowpath_total` was added to allow users to monitor how many leader elections are updated non-optimistically.
   ([#122069](https://github.com/kubernetes/kubernetes/pull/122069), [@linxiulei](https://github.com/linxiulei))
- Locked the GA feature-gate `ConsistentHTTPGetHandlers` to default.

- A pod that the Kubelet rejects was still considered as being accepted for a brief period of time after rejection, which might cause some pods to be rejected briefly that could fit on the node.  A pod that is still terminating (but has status indicating it has failed) may also still be consuming resources and so should also be considered. ([#104817](https:/...

  
  Action required for custom scheduler plugin developers:
  Plugins **have to** implement a QueueingHint for Pod/Update event if the rejection from them could be resolved by updating unscheduled Pods themselves.
  Example: suppose you develop a custom plugin that denies Pods that have a `schedulable=false` label.