/**
   * A sensible definition of {@link #pollFirstEntry} in terms of the {@code iterator} of {@code
   * entrySet}. If you override {@code entrySet}, you may wish to override {@code pollFirstEntry} to
   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardPollFirstEntry() {
    return Iterators.pollNext(entrySet().iterator());
  }

  @Override
  public @Nullable Entry<K, V> pollLastEntry() {

   *     have the same bit length
   */
  public static HashCode combineOrdered(Iterable<HashCode> hashCodes) {
    Iterator<HashCode> iterator = hashCodes.iterator();
    checkArgument(iterator.hasNext(), "Must be at least 1 hash code to combine.");
    int bits = iterator.next().bits();
    byte[] resultBytes = new byte[bits / 8];
    for (HashCode hashCode : hashCodes) {

   * <p>Iterators from the returned map are at least <i>weakly consistent</i>: they are safe for
   * concurrent use, but if the cache is modified (including by eviction) after the iterator is
   * created, it is undefined which of the changes (if any) will be reflected in that iterator.
   */
  @J2ktIncompatible // Thread safety complexity
  ConcurrentMap<K, V> asMap();

  /**

   * (`implements Function<@PolyNull A, @PolyNull B>`), at least as far as I know.)
   */
  public Iterable<B> convertAll(Iterable<? extends A> fromIterable) {
    checkNotNull(fromIterable, "fromIterable");
    return () ->
        new Iterator<B>() {
          private final Iterator<? extends A> fromIterator = fromIterable.iterator();

          @Override
          public boolean hasNext() {

        verify(tree, times(1)).acquire();
        verify(tree, times(1)).release();
    }

    @Test
    @DisplayName("Happy path: iterates entries, fetchMore(), then closes with FindClose2")
    void iteratesAndFetchesMoreThenCloses() throws Exception {
        // Arrange: program send() to simulate first, next, next(NO_MORE_FILES)

// See `org.gradle.kotlin.dsl.internal.sharedruntime.codegen.ApiTypeProviderKt.mappedTypeStrings`
private
val collectionTypeStrings =
    mapOf(
        "java.lang.Iterable" to "kotlin.collections.Iterable",
        "java.util.Iterator" to "kotlin.collections.Iterator",
        "java.util.ListIterator" to "kotlin.collections.ListIterator",
        "java.util.Collection" to "kotlin.collections.Collection",

  }

  private static <T> List<T> defensiveCopy(T... array) {
    return defensiveCopy(Arrays.asList(array));
  }

  static <T> List<T> defensiveCopy(Iterable<T> iterable) {
    ArrayList<T> list = new ArrayList<>();
    for (T element : iterable) {
      list.add(checkNotNull(element));
    }
    return list;
  }

  private Predicates() {}

   * @since 11.0 (generics widened in 13.0)
   */
  public static <T> Iterable<T> presentInstances(
      Iterable<? extends Optional<? extends T>> optionals) {
    checkNotNull(optionals);
    return () ->
        new AbstractIterator<T>() {
          private final Iterator<? extends Optional<? extends T>> iterator =
              checkNotNull(optionals.iterator());

          @Override

    }

    @Override
    public boolean isEmpty() {
      synchronized (mutex) {
        return delegate().isEmpty();
      }
    }

    @Override
    public Iterator<E> iterator() {
      return delegate().iterator(); // manually synchronized
    }

    @Override
    public boolean remove(@Nullable Object o) {
      synchronized (mutex) {
        return delegate().remove(o);
      }
    }

    }

    @Override
    public boolean isEmpty() {
      synchronized (mutex) {
        return delegate().isEmpty();
      }
    }

    @Override
    public Iterator<E> iterator() {
      return delegate().iterator(); // manually synchronized
    }

    @Override
    public Spliterator<E> spliterator() {
      synchronized (mutex) {
        return delegate().spliterator();
      }
    }