}

    @Override
    public Iterator<K> iterator() {
      return keySetIterator();
    }

    @Override
    public void clear() {
      CompactHashMap.this.clear();
    }
  }

  Iterator<K> keySetIterator() {
    Map<K, V> delegate = delegateOrNull();
    if (delegate != null) {
      return delegate.keySet().iterator();
    }
    return new Itr<K>() {
      @Override

    testers.add(ListSubListTester.class);
    testers.add(ListToArrayTester.class);
    return testers;
  }

  /**
   * Specifies {@link CollectionFeature#KNOWN_ORDER} for all list tests, since lists have an
   * iteration ordering corresponding to the insertion order.
   */
  @Override
  public TestSuite createTestSuite() {
    withFeatures(KNOWN_ORDER);
    return super.createTestSuite();
  }

  @Override

"^smb://.*"        → smbClient
"^storage://.*"    → storageClient
```

### Services

**UrlQueueService**: URL queue management (FIFO), duplicate detection via `visited()`
**DataService**: Access result persistence, iteration

**Implementations**:
- `UrlQueueServiceImpl`, `DataServiceImpl`: In-memory (default)
- `OpenSearchDataService`: OpenSearch backend (persistent)

### Processing Pipeline

```

    }

    @Spy
    SecurityBlob spyBlob = new SecurityBlob();

    // Illustrates Mockito interaction verification by spying on set() and validating behavior
    @Test
    @DisplayName("Mockito spy: verify set() interaction and resulting behavior")
    void spy_verifySetInteraction() {
        // Arrange
        byte[] payload = new byte[] { 5, 6 };

        // Act

      UnmodifiableIterator<T> iterator) {
    return checkNotNull(iterator);
  }

  /**
   * Returns the number of elements remaining in {@code iterator}. The iterator will be left
   * exhausted: its {@code hasNext()} method will return {@code false}.
   */
  public static int size(Iterator<?> iterator) {
    long count = 0L;
    while (iterator.hasNext()) {
      iterator.next();
      count++;

    testers.add(ListSubListTester.class);
    testers.add(ListToArrayTester.class);
    return testers;
  }

  /**
   * Specifies {@link CollectionFeature#KNOWN_ORDER} for all list tests, since lists have an
   * iteration ordering corresponding to the insertion order.
   */
  @Override
  public TestSuite createTestSuite() {
    withFeatures(KNOWN_ORDER);
    return super.createTestSuite();
  }

  @Override

      return map;
    }

    @Override
    public Iterator<K> iterator() {
      return keyIterator(map().entrySet().iterator());
    }

    @Override
    public void forEach(Consumer<? super K> action) {
      checkNotNull(action);
      // avoids entry allocation for those maps that allocate entries on iteration
      map.forEach((k, v) -> action.accept(k));
    }

    @Override

import java.util.Map;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * Used to represent the order of elements in a data structure that supports different options for
 * iteration order guarantees.
 *
 * <p>Example usage:
 *
 * {@snippet :
 * MutableGraph<Integer> graph =
 *     GraphBuilder.directed().nodeOrder(ElementOrder.<Integer>natural()).build();
 * }
 *

import java.util.Map;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * Used to represent the order of elements in a data structure that supports different options for
 * iteration order guarantees.
 *
 * <p>Example usage:
 *
 * {@snippet :
 * MutableGraph<Integer> graph =
 *     GraphBuilder.directed().nodeOrder(ElementOrder.<Integer>natural()).build();
 * }
 *

     * comparator.
     *
     * <p>The sort order is stable, that is, if two entries have values that compare as equivalent,
     * the entry that was inserted first will be first in the built map's iteration order.
     *
     * @throws IllegalStateException if this method was already called
     * @since 19.0
     */
    @CanIgnoreReturnValue
    @Override