- Improved memory usage of `kube-scheduler` by dropping the `.metadata.managedFields` field that `kube-scheduler` doesn't require. ([#119556](https://github.com/kubernetes/kubernetes/pull/119556), [@linxiulei](https://github.com/linxiulei))

   * close or flush the reader.
   *
   * <p>This is identical to {@link #copy(Readable, Appendable)} but optimized for these specific
   * types. CharBuffer has poor performance when being written into or read out of so round tripping
   * all the bytes through the buffer takes a long time. With these specialized types we can just
   * use a char array.
   *
   * @param from the object to read from
   * @param to the object to write to

  - warn - perform server-side validation and warn on any invalid fields (but ultimately let the request succeed by dropping any invalid fields from the object). If validation is not available on the server, perform no validation.
  - false/ignore - perform no validation, silently dropping invalid fields from the object. ([#108350](https://github.com/kubernetes/kubernetes/pull/108350), [@kevindelgado](https://github.com/kevindelgado))

- Commands like `kubectl apply` now return errors if schema-invalid annotations are specified, rather than silently dropping the entire annotations section. ([#83552](https://github.com/kubernetes/kubernetes/pull/83552), [@liggitt](https://github.com/liggitt))

capering wildly about.

  `Change lobster's again!' yelled the Gryphon at the top of its voice.

  `Back to land again, and that's all the first figure,' said the
Mock Turtle, suddenly dropping his voice; and the two creatures,
who had been jumping about like mad things all this time, sat
down again very sadly and quietly, and looked at Alice.

  `It must be a very pretty dance,' said Alice timidly.

- `kubectl apply` now coerces `null` values for labels and annotations in manifests to empty string values, 
consistent with typed JSON metadata decoding, rather than dropping all labels and annotations ([#129257](https://github.com/kubernetes/kubernetes/pull/129257), [@liggitt](https://github.com/liggitt)) [SIG API Machinery]

### Feature

				// Next loop will catch it.
			case <-pingTimer:
				if !m.doPing(respHandler) {
					return
				}
				goto sendResp
			}
		case <-pingTimer:
			if !m.doPing(respHandler) {
				return
			}
		}
	}
}

// doPing checks last ping time and sends another ping.
func (m *muxClient) doPing(respHandler chan<- Response) (ok bool) {
	m.respMu.Lock()
	if m.closed {

* Implement graceful shutdown of the kube-apiserver by waiting for open connections to finish before exiting. Moreover, the audit backend will stop dropping events on shutdown. ([#53695](https://github.com/kubernetes/kubernetes/pull/53695), [@hzxuzhonghu](https://github.com/hzxuzhonghu))

    assertLessThan(NEW, TERMINATED);

    assertLessThan(STARTING, RUNNING);
    assertLessThan(STARTING, STOPPING);
    assertLessThan(STARTING, FAILED);

    assertLessThan(RUNNING, STOPPING);
    assertLessThan(RUNNING, FAILED);

    assertLessThan(STOPPING, FAILED);
    assertLessThan(STOPPING, TERMINATED);
  }

  private static <T extends Comparable<? super T>> void assertLessThan(T a, T b) {

    return new ListenerCallQueue.Event<Listener>() {
      @Override
      public void call(Listener listener) {
        listener.stopping(from);
      }

      @Override
      public String toString() {
        return "stopping({from = " + from + "})";
      }
    };
  }

  private final Monitor monitor = new Monitor();