return indexBeforeRemove - 1;
  }

  @Override
  public Iterator<E> iterator() {
    Set<E> delegate = delegateOrNull();
    if (delegate != null) {
      return delegate.iterator();
    }
    return new Iterator<E>() {
      int expectedMetadata = metadata;
      int currentIndex = firstEntryIndex();
      int indexToRemove = -1;

        }

        int removed = 0;
        final Iterator<Map.Entry<String, ChatSession>> iterator = sessionCache.entrySet().iterator();
        while (iterator.hasNext()) {
            final Map.Entry<String, ChatSession> entry = iterator.next();
            if (isExpired(entry.getValue())) {
                iterator.remove();
                removed++;
            }
        }

    assertThat(DoubleMath.mean(ImmutableList.of(11, -22, 44, -88).iterator()))
        .isWithin(1.0e-10)
        .of(-13.75);
    assertThat(DoubleMath.mean(ImmutableList.of(11).iterator())).isWithin(1.0e-10).of(11);
    assertThrows(
        IllegalArgumentException.class,
        () -> DoubleMath.mean(ImmutableList.<Integer>of().iterator()));
  }

  @GwtIncompatible // DoubleMath.mean

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.jspecify.annotations.Nullable;

/**
 * Note this class is a copy of {@link com.google.common.collect.AbstractIterator} (for dependency
 * reasons).
 */
@GwtCompatible
abstract class AbstractIterator<T extends @Nullable Object> implements Iterator<T> {
  private State state = State.NOT_READY;

        size(), SPLITERATOR_CHARACTERISTICS | Spliterator.SIZED) {
      final UnmodifiableIterator<E> iterator = iterator();

      @Override
      public boolean tryAdvance(Consumer<? super E> action) {
        if (iterator.hasNext()) {
          action.accept(iterator.next());
          return true;
        } else {
          return false;
        }
      }

      @Override

                }
            });
        }
    }

    @Override
    public Iterator<Lifecycle> iterator() {
        return stream().toList().iterator();
    }

    @Override
    public Stream<Lifecycle> stream() {
        return providers.stream().map(ExtensibleEnumProvider::provides).flatMap(Collection::stream);
    }

    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder().expireAfterWrite(1000, MILLISECONDS).ticker(fakeTicker).build();

    cache.put(10, 20);
    Iterator<Integer> iterator = cache.asMap().values().iterator();
    iterator.next();
    iterator.remove();

    assertThat(cache.size()).isEqualTo(0);
  }

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.GwtCompatible;
import java.util.Queue;
import org.jspecify.annotations.Nullable;

/**
 * An Iterator implementation which draws elements from a queue, removing them from the queue as it
 * iterates. This class is not thread safe.
 */
@GwtCompatible

      return ImmutableMap.this.hashCode();
    }

    @Override
    UnmodifiableIterator<Entry<K, ImmutableSet<V>>> entryIterator() {
      final Iterator<Entry<K, V>> backingIterator = ImmutableMap.this.entrySet().iterator();
      return new UnmodifiableIterator<Entry<K, ImmutableSet<V>>>() {
        @Override
        public boolean hasNext() {
          return backingIterator.hasNext();
        }

   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(Collection<T> collection) {
    // return collection::iterator;
    return new Iterable<T>() {
      @Override
      public Iterator<T> iterator() {
        return collection.iterator();
      }
    };
  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(ImmutableDoubleArray.of())