### Beta

- Promote WatchBookmark feature to beta and enable it by default.
  With WatchBookmark feature, clients are able to request watch events with BOOKMARK type. Clients should not assume bookmarks are returned at any specific interval, nor may they assume the server will send any BOOKMARK event during a session. ([#79786](https://github.com/kubernetes/kubernetes/pull/79786), [@wojtek-t](https://github.com/wojtek-t))

    h.update(name)
    for r in revs:
      h.update(b' ')
      h.update(r)
    h.update(b'\n')
  if (b'bookmarks' in peer.listkeys(b'namespaces')):
    for name, rev in peer.listkeys(b'bookmarks').items():
      h.update(name)
      h.update(b'=')
      h.update(rev)
      h.update(b'\n')
  print('r1:'+base64.standard_b64encode(h.digest()).decode('utf-8'))

@command(b'golookup', [], _('url rev'), norepo=True)

- Implemented API streaming for the `watch-cache`
  
  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. ([#110960](https://github.com/kubernetes/kubernetes/pull/110960), [@p0lyn0mial](https://github.com/p0lyn0mial))
- Introduced API for streaming.
  

- The synthetic "Bookmark" event for the watch stream requests will now include a new annotation: `kubernetes.io/initial-events-list-blueprint`. THe annotation contains an empty, versioned list that is encoded in the requested format (such as protobuf, JSON, or CBOR), then...

- 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))

- Client-go: informer stores now keep track the resourceVersion they are synced to (via add/update/delete events, or replace calls, or bookmark events), and provide a `LastStoreSyncResourceVersion` method to obtain this resource version. This method can return `""` if the store has not been synced to yet, and depends on the AtomicFIFO feature being enabled. ([#134827](https://github.com...

- Removed the `kubernetes.io/initial-events-list-blueprint` annotation from the synthetic "Bookmark" event in watch stream requests. ([#132326](https://github.com/kubernetes/kubernetes/pull/132326), [@p0lyn0mial](https://github.com/p0lyn0mial))

- Client-go/reflector: warns when the bookmark event for initial events hasn't been received ([#124614](https://github.com/kubernetes/kubernetes/pull/124614), [@p0lyn0mial](https://github.com/p0lyn0mial)) [SIG API Machinery]