@J2ktIncompatible
        private void writeObject(ObjectOutputStream stream) throws IOException {
      stream.defaultWriteObject();
      stream.writeObject(factory);
      stream.writeObject(backingMap());
    }

    @GwtIncompatible
    @J2ktIncompatible
        @SuppressWarnings("unchecked") // reading data stored by writeObject

    @J2ktIncompatible
        private void writeObject(ObjectOutputStream stream) throws IOException {
      stream.defaultWriteObject();
      stream.writeObject(factory);
      stream.writeObject(backingMap());
    }

    @GwtIncompatible
    @J2ktIncompatible
        @SuppressWarnings("unchecked") // reading data stored by writeObject

    even for a single call.

    Interceptors that rewrite or replace the request body may now inadvertently interfere with
    duplex request bodies. Such interceptors should check `RequestBody.isDuplex()` and avoid
    accessing the request body when it is.

    Duplex calls require HTTP/2. If HTTP/1 is established instead the duplex call will fail. The
    most common use of duplex calls is [gRPC][grpc_http2].

  /**
   * Returns a successful {@code ListenableFuture<Void>}. This method is equivalent to {@code
   * immediateFuture(null)} except that it is restricted to produce futures of type {@code Void}.
   *
   * @since 29.0
   */
  @SuppressWarnings("unchecked")
  public static ListenableFuture<@Nullable Void> immediateVoidFuture() {
    return (ListenableFuture<@Nullable Void>) ImmediateFuture.NULL;
  }

  /**

 * }
 * }
 *
 * <p>so that a hypothetical bad caller of this method, such as:
 *
 * {@snippet :
 * void exampleBadCaller() {
 *   double d = sqrt(-1.0);
 * }
 * }
 *
 * <p>would be flagged as having called {@code sqrt()} with an illegal argument.
 *
 * <h3>Performance</h3>
 *
 * <p>Avoid passing message arguments that are expensive to compute; your code will always compute

    return cycle(Lists.newArrayList(elements));
  }

  /**
   * Returns an Iterator that walks the specified array, nulling out elements behind it. This can
   * avoid memory leaks when an element is no longer necessary.
   *
   * <p>This method accepts an array with element type {@code @Nullable T}, but callers must pass an

    /** Drains the reference queues used by this segment, if any. */
    @GuardedBy("this")
    void maybeDrainReferenceQueues() {}

    /** Clears the reference queues used by this segment, if any. */
    void maybeClearReferenceQueues() {}

    /** Sets the value of the given {@code entry}. */
    void setValue(E entry, V value) {
      this.map.entryHelper.setValue(self(), entry, value);
    }

* 'kubectl describe pv' now shows events ([#27431](https://github.com/kubernetes/kubernetes/pull/27431), [@jsafrane](https://github.com/jsafrane))
* AWS kube-up: set net.ipv4.neigh.default.gc_thresh1=0 to avoid ARP over-caching ([#27682](https://github.com/kubernetes/kubernetes/pull/27682), [@justinsb](https://github.com/justinsb))

     * that is inconsistent with {@link Object#equals(Object)}.
     */
    public ImmutableSet<@NonNull E> immutableCopy() {
      // Not using ImmutableSet.copyOf() to avoid iterating thrice (isEmpty, size, iterator).
      int maxSize = maxSize();
      if (maxSize == 0) {
        return ImmutableSet.of();
      }

     * * **Unreachable proxy servers.** A [ProxySelector] can be used to
     *   attempt multiple proxy servers in sequence, eventually falling back to a direct
     *   connection.
     *
     * Set this to false to avoid retrying requests when doing so is destructive. In this case the
     * calling application should do its own recovery of connectivity failures.
     */
    fun retryOnConnectionFailure(retryOnConnectionFailure: Boolean) =