*
 * @author George van den Driessche
 */
@GwtCompatible
public final class TesterRequirements {
  private final Set<Feature<?>> presentFeatures;
  private final Set<Feature<?>> absentFeatures;

  public TesterRequirements(Set<Feature<?>> presentFeatures, Set<Feature<?>> absentFeatures) {
    this.presentFeatures = copyToSet(presentFeatures);
    this.absentFeatures = copyToSet(absentFeatures);
  }

### SIG-instrumentation

No feature work, but a large refactoring of metrics-server as well as a number of bug fixes.

### SIG-node

SIG-node graduated the PodShareProcessNamespace feature from alpha to beta.  This feature allows a pod spec to request that all containers in a pod share a common process namespaces.

### CSI Service Account Token

CSI Service Account Token feature moves to Beta in 1.21. This feature improves the security posture and allows CSI drivers to receive pods' [bound service account tokens](https://github.com/kubernetes/enhancements/blob/master/keps/sig-auth/1205-bound-service-account-tokens/README.md). This feature also provides a knob to re-publish volumes so that short-lived volumes can be refreshed.

name: Enhancement Tracking Issue
description: Provide supporting details for a feature in development
labels: kind/feature
body:
  - type: textarea
    id: feature
    attributes:
      label: What would you like to be added?
      description: |
        Feature requests are unlikely to make progress as issues. Please consider engaging with SIGs on slack and mailing lists, instead.

    assertFalse(future.isCancelled());

    ExecutorService executor = newSingleThreadExecutor();

    try {
      Future<Boolean> getResult = executor.submit(() -> future.get());

      // Release the future value.
      latch.countDown();

      assertTrue(getResult.get(10, SECONDS));
    } finally {
      executor.shutdownNow();
    }

    assertTrue(future.isDone());

- HTTP/2 connection health check is enabled by default in all Kubernetes clients. The feature should work out-of-the-box. If needed, users can tune the feature via the HTTP2_READ_IDLE_TIMEOUT_SECONDS and HTTP2_PING_TIMEOUT_SECONDS environment variables. The feature is disabled if HTTP2_READ_IDLE_TIMEOUT_SECONDS is set to 0. ([#96778](https://github.com/kubernetes/kubernetes/pull/96778), [@caesarxuchao](https://github.com/caesarxuchao))...

          .that(returnType.getComponentType())
          .isEqualTo(annotationClass.getDeclaringClass());
    }
  }

  // This is public so that tests for Feature enums we haven't yet imagined
  // can reuse it.
  public static <E extends Enum<?> & Feature<?>> void assertGoodFeatureEnum(
      Class<E> featureEnumClass) {
    Class<?>[] classes = featureEnumClass.getDeclaredClasses();
    for (Class<?> containedClass : classes) {

      // at the beginning of the loop.
      int i = 0;
      for (ListenableFuture<? extends InputT> future : futures) {
        int index = i++;
        if (future.isDone()) {
          processAllMustSucceedDoneFuture(index, future);
        } else {
          future.addListener(
              () -> processAllMustSucceedDoneFuture(index, future), directExecutor());
        }
      }
    } else {
      /*

   * but one.
   */
  REJECTS_DUPLICATES_AT_CREATION,

  GENERAL_PURPOSE(SUPPORTS_PUT, SUPPORTS_REMOVE);

  private final Set<Feature<? super Map>> implied;

  MapFeature(Feature<? super Map>... implied) {
    this.implied = copyToSet(implied);
  }

  @Override
  public Set<Feature<? super Map>> getImpliedFeatures() {
    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation

- Removed the `CronJobTimeZone` feature gate (the feature is stable and always enabled)
  - Removed the `JobMutableNodeSchedulingDirectives` feature gate (the feature is stable and always enabled)