* test with reference to the same "lock-like object", and then their interactions with that object
 * are choreographed via the various methods on this class.
 *
 * <p>A "lock-like object" is really any object that may be used for concurrency control. If the
 * {@link #callAndAssertBlocks} method is ever called in a test, the lock-like object must have a

  public static <T> Collector<T, ?, Optional<T>> toOptional() {
    return (Collector) TO_OPTIONAL;
  }

  private static final Object NULL_PLACEHOLDER = new Object();

  private static final Collector<@Nullable Object, ?, @Nullable Object> ONLY_ELEMENT =
      Collector.<@Nullable Object, ToOptionalState, @Nullable Object>of(
          ToOptionalState::new,
          (state, o) -> state.add((o == null) ? NULL_PLACEHOLDER : o),

			object: "",
		},
		// Test case 4 many separators and object is a directory.
		{
			path:   "/bucket/object/1/",
			bucket: "bucket",
			object: "object/1/",
		},
		// Test case 5 object has many trailing separators.
		{
			path:   "/bucket/object/1///",
			bucket: "bucket",
			object: "object/1///",
		},
		// Test case 6 object has only trailing separators.
		{
			path:   "/bucket/object///////",

  }

  static boolean equalsImpl(Multimap<?, ?> multimap, @Nullable Object object) {
    if (object == multimap) {
      return true;
    }
    if (object instanceof Multimap) {
      Multimap<?, ?> that = (Multimap<?, ?>) object;
      return multimap.asMap().equals(that.asMap());
    }
    return false;
  }

  }

  static boolean equalsImpl(Multimap<?, ?> multimap, @Nullable Object object) {
    if (object == multimap) {
      return true;
    }
    if (object instanceof Multimap) {
      Multimap<?, ?> that = (Multimap<?, ?>) object;
      return multimap.asMap().equals(that.asMap());
    }
    return false;
  }

 *
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public final class DerivedCollectionGenerators {
  public static class MapEntrySetGenerator<K extends @Nullable Object, V extends @Nullable Object>
      implements TestSetGenerator<Entry<K, V>>, DerivedGenerator {
    private final OneSizeTestContainerGenerator<Map<K, V>, Entry<K, V>> mapGenerator;

    public MapEntrySetGenerator(

    fun platformMatches(platform: String): Matcher<Any> =
      object : BaseMatcher<Any>() {
        override fun describeTo(description: Description) {
          description.appendText(platform)
        }

        override fun matches(item: Any?): Boolean = getPlatformSystemProperty() == platform
      }

    fun fromMajor(version: Int): Matcher<PlatformVersion> =
      object : TypeSafeMatcher<PlatformVersion>() {

      @Override
      public ImmutableMultiset<Object> create(List<?> keys) {
        ImmutableMultiset.Builder<Object> builder = ImmutableMultiset.builder();
        for (Object o : keys) {
          builder.add(o);
        }
        return builder.build();
      }
    },
    BUILDER_ADD_ALL_COLLECTION {
      @Override
      public ImmutableMultiset<Object> create(List<?> keys) {

  }

  public void testAwaitClear() {
    WeakReference<Object> ref = new WeakReference<>(new Object());
    GcFinalization.awaitClear(ref);
    assertNull(ref.get());
  }

  public void testAwaitDone_finalizationPredicate() {
    WeakHashMap<Object, Object> map = new WeakHashMap<>();
    map.put(new Object(), Boolean.TRUE);
    GcFinalization.awaitDone(
        new FinalizationPredicate() {

 */
@GwtCompatible
abstract class AbstractTable<
        R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>
    implements Table<R, C, V> {

  @Override
  public boolean containsRow(@Nullable Object rowKey) {
    return Maps.safeContainsKey(rowMap(), rowKey);
  }

  @Override
  public boolean containsColumn(@Nullable Object columnKey) {
    return Maps.safeContainsKey(columnMap(), columnKey);
  }