*       ImmutableMap.get} returns {@code @Nullable E} because the method can return {@code null}
 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this

 *       ImmutableMap.get} returns {@code @Nullable E} because the method can return {@code null}
 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this

 *       ImmutableMap.get} returns {@code @Nullable E} because the method can return {@code null}
 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this

 *       ImmutableMap.get} returns {@code @Nullable E} because the method can return {@code null}
 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>Kotlin, for which it makes the type-variable usage (a) a Kotlin platform type when the type
 *       argument is non-nullable and (b) nullable when the type argument is nullable. We use this

 *
 * <p>To decouple components, we recommend a dependency-injection framework. For Android code, most
 * apps use <a href="https://dagger.dev">Dagger</a>. For server code, common options include <a
 * href="https://github.com/google/guice/wiki/Motivation">Guice</a> and <a
 * href="https://docs.spring.io/spring-framework/docs/current/reference/html/core.html#beans-introduction">Spring</a>.

   * requireNonNull} or the like just to assert that.
   *
   * <p>{@code EqualsTester} will always check that every object it is given returns false from
   * {@code equals(null)}, so it is neither useful nor allowed to include a null value in any
   * equality group.
   */
  @CanIgnoreReturnValue
  public EqualsTester addEqualityGroup(@Nullable Object @Nullable ... equalityGroup) {
    checkNotNull(equalityGroup);

 * address in IPv4 or IPv6 notation, or a domain name.
 *
 * <p>Because this class is intended to represent host specifiers which can reasonably be used in a
 * URI, the domain name case is further restricted to include only those domain names which end in a
 * recognized public suffix; see {@link InternetDomainName#isPublicSuffix()} for details.
 *
 * <p>Note that no network lookups are performed by any {@code HostSpecifier} methods. No attempt is

 *         if (s != null) {
 *           return s;
 *         }
 *       }
 *       return endOfData();
 *     }
 *   };
 * }
 * }</pre>
 *
 * <p>This class supports iterators that include null elements.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
// When making changes to this class, please also update the copy at
// com.google.common.base.AbstractIterator
@GwtCompatible

   * TODO: improve this and other implementations and move out of this framework
   * for wider use
   *
   * TODO: could we incorporate the overriding logic from AbstractListTester, by
   * examining whether the features include KNOWN_ORDER?
   */
  protected void expectContents(Collection<E> expected) {
    Helpers.assertEqualIgnoringOrder(expected, actualContents());
  }

  protected void expectUnchanged() {

   * @throws IllegalArgumentException if {@code node} is not an element of this graph
   */
  @Override
  Set<N> successors(N node);

  /**
   * Returns a live view of the edges in this graph whose endpoints include {@code node}.
   *
   * <p>This is equal to the union of incoming and outgoing edges.
   *
   * <p>If {@code node} is removed from the graph after this method is called, the {@code Set}