- Introduces new alpha functionality to the reflector, allowing user to enable API streaming.
  
  To activate this feature, users can set the `ENABLE_CLIENT_GO_WATCH_LIST_ALPHA` environmental variable.
  It is important to note that the server must support streaming for this feature to function properly.
  If streaming is not supported by the server, the reflector will revert to the previous method

redirects.  If nodes are configured to respond to CRI streaming requests on a different host interface than what the apiserver makes requests on (only the case if not using the built-in dockershim & setting the kubelet flag `--redirect-container-streaming=true`), then these requests will be broken. In that case, the feature can be temporarily disabled until the node configuration is corrected. We suggest setting `--redirect-container-streaming=false` on the kubelet to avoid issues.([#72552](https...

- Implemented API for streaming for the `etcd` store implementation.
  When `sendInitialEvents ListOption` is set together with `watch=true`, it begins the watch stream with synthetic init events followed by a synthetic `Bookmark`, after which the server continues streaming events. ([#119557](https://github.com/kubernetes/kubernetes/pull/119557), [@p0lyn0mial](https://github.com/p0lyn0mial))

#### kubelet:

* Added proxy for container streaming in kubelet for streaming auth. ([#64006](https://github.com/kubernetes/kubernetes/pull/64006), [@Random-Liu](https://github.com/Random-Liu))

- Moved `k8s.io/kubernetes/pkg/kubelet/cri/streaming` package to `k8s.io/kubelet/pkg/cri/streaming`. ([#118253](https://github.com/kubernetes/kubernetes/pull/118253), [@saschagrunert](https://github.com/saschagrunert)) [SIG Node, Release and Security]

* Use full package path for definition name in OpenAPI spec ([#40124](https://github.com/kubernetes/kubernetes/pull/40124), [@mbohlool](https://github.com/mbohlool))
* Follow redirects for streaming requests (exec/attach/port-forward) in the apiserver by default (alpha -> beta). ([#40039](https://github.com/kubernetes/kubernetes/pull/40039), [@timstclair](https://github.com/timstclair))

- Handle slow CronJob lister in CronJob controller v2 and improve memory footprint. ([#96443](https://github.com/kubernetes/kubernetes/pull/96443), [@alaypatel07](https://github.com/alaypatel07)) [SIG Apps]
- --redirect-container-streaming is no longer functional. The flag will be removed in v1.22 ([#95935](https://github.com/kubernetes/kubernetes/pull/95935), [@tallclair](https://github.com/tallclair)) [SIG Node]

 - Default `StreamingProxyRedirects` to disabled. If there is a >= 2 version skew between master and nodes, and the old nodes were enabling `--redirect-container-streaming`, this will break them. In this case, the `StreamingProxyRedirects` can still be manually enabled. ([#101647](https://github.com/kubernetes/kubernetes/pull/101647), [@pacoxu](https://github.com/pacoxu))

  // MatchLabelKeys is a set of pod label keys to select the pods over which
  // spreading will be calculated. The keys are used to lookup values from the
  // incoming pod labels, those key-value labels are ANDed with labelSelector
  // to select the group of existing pods over which spreading will be calculated
  // for the incoming pod. The same key is forbidden to exist in both MatchLabelKeys and LabelSelector.