### API changes and improvements for ephemeral containers

The API used to create [Ephemeral Containers](https://kubernetes.io/docs/concepts/workloads/pods/ephemeral-containers/) changed in 1.22. The Ephemeral Containers feature is alpha and disabled by default, and the new API does not work with clients that attempt to use the old API.

        return new TreeSet<E>(contents);
      }
    },
    UnmodifiableSetImpl {
      @Override
      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {
        return unmodifiableSet(new HashSet<E>(contents));
      }
    },
    SynchronizedSetImpl {
      @Override
      public <E extends Comparable<E>> Set<E> create(Collection<E> contents) {

    @Test
    @DisplayName("Should return negotiate contexts")
    void testGetNegotiateContexts() throws Exception {
        // Given
        NegotiateContextResponse[] contexts = new NegotiateContextResponse[2];
        contexts[0] = new EncryptionNegotiateContext();
        contexts[1] = new PreauthIntegrityNegotiateContext();
        setPrivateField(response, "negotiateContexts", contexts);

        // When

 *   <li>chaining methods which return a new {@code FluentIterable} based in some way on the
 *       contents of the current one (for example {@link #transform})
 *   <li>element extraction methods which facilitate the retrieval of certain elements (for example
 *       {@link #last})
 *   <li>query methods which answer questions about the {@code FluentIterable}'s contents (for
 *       example {@link #anyMatch})

    final ArrayList<E> contents;

    public Builder() {
      this.contents = Lists.newArrayList();
    }

    Builder(int initialCapacity) {
      this.contents = Lists.newArrayListWithCapacity(initialCapacity);
    }

    @CanIgnoreReturnValue
    @Override
    public Builder<E> add(E element) {
      contents.add(checkNotNull(element));
      return this;
    }

    // This benchmark has no concept of "noWorkToDo".
    String lhs = testString;
    String rhs = testString.toUpperCase();

    boolean dummy = false;
    for (int i = 0; i < reps; i++) {
      dummy ^= Ascii.equalsIgnoreCase(lhs, rhs);
    }
    return dummy;
  }

  @Benchmark
  boolean equalsIgnoreCaseJDK(int reps) {
    // This benchmark has no concept of "noWorkToDo".
    String lhs = testString;

        // Then
        NegotiateContextRequest[] contexts = request.getNegotiateContexts();
        assertNotNull(contexts);
        assertEquals(2, contexts.length);

        // Verify preauth context
        assertTrue(contexts[0] instanceof PreauthIntegrityNegotiateContext);
        assertEquals(PreauthIntegrityNegotiateContext.NEGO_CTX_PREAUTH_TYPE, contexts[0].getContextType());

        // Verify encryption context

        void testNullContextInArray() {
            CreateContextRequest[] contexts = new CreateContextRequest[4];
            contexts[0] = new MockCreateContextRequest("FIRST");
            contexts[1] = null; // Null context
            contexts[2] = new MockCreateContextRequest("THIRD");
            contexts[3] = new MockCreateContextRequest("FOURTH");

            byte[] buffer = new byte[256];

    elems = new CollectionBenchmarkSampleData(elements);
    contents = new HashMap<>();
    for (Element key : elems.getValuesInSet()) {
      contents.put(key, key);
    }
    map = mapsImpl.create(contents);
  }

  @Benchmark
  @Footprint(exclude = Element.class)
  public Map<Element, Element> create() throws Exception {
    return mapsImpl.create(contents);
  }

  @Benchmark
  public int iterate() {

      for (List<Integer> contents : SAMPLE_INPUTS) {
        for (int toRemove = 0; toRemove < 10; toRemove++) {
          assertEquals(
              contents.contains(toRemove) && EVEN.apply(toRemove),
              filter(createUnfiltered(contents), EVEN).remove(toRemove));
        }
      }
    }

    public void testContains() {
      for (List<Integer> contents : SAMPLE_INPUTS) {