import static com.google.common.collect.testing.Helpers.assertEqualIgnoringOrder;
import static com.google.common.collect.testing.Helpers.assertEqualInOrder;
import static com.google.common.collect.testing.Platform.format;
import static java.util.Arrays.asList;
import static java.util.Collections.unmodifiableSet;
import static junit.framework.Assert.assertEquals;
import static junit.framework.Assert.assertFalse;

     * ImmutableSetMultimap#builder}.
     */
    public Builder() {
      super();
    }

    @Override
    Collection<V> newMutableValueCollection() {
      return Platform.preservesInsertionOrderOnAddsSet();
    }

    /** Adds a key-value mapping to the built multimap if it is not already present. */
    @CanIgnoreReturnValue
    @Override

     * the parameter and return type both to be platform types. As a result, Kotlin permits calls
     * that can lead to NullPointerException. That's unfortunate. But hopefully most Kotlin callers
     * use `get(key) ?: defaultValue` instead of this method, anyway.
     */
    V result = get(key);

  @VisibleForTesting
  static class ArbitraryOrdering extends Ordering<@Nullable Object> {

    private final AtomicInteger counter = new AtomicInteger(0);
    private final ConcurrentMap<Object, Integer> uids =
        Platform.tryWeakKeys(new MapMaker()).makeMap();

    private Integer getUid(Object obj) {
      Integer uid = uids.get(obj);
      if (uid == null) {
        // One or more integer values could be skipped in the event of a race

    @CheckForNull volatile Waiter next;

    /**
     * Constructor for the TOMBSTONE, avoids use of ATOMIC_HELPER in case this class is loaded
     * before the ATOMIC_HELPER. Apparently this is possible on some android platforms.
     */
    Waiter(boolean unused) {}

    Waiter() {
      // avoid volatile write, write is made visible by subsequent CAS on waiters field
      ATOMIC_HELPER.putThread(this, Thread.currentThread());
    }

  /**
   * The HTTP <a href="https://wicg.github.io/ua-client-hints/#sec-ch-ua-platform">{@code
   * Sec-CH-UA-Platform}</a> header field name.
   *
   * @since 30.0
   */
  public static final String SEC_CH_UA_PLATFORM = "Sec-CH-UA-Platform";
  /**
   * The HTTP <a href="https://wicg.github.io/ua-client-hints/#sec-ch-ua-platform-version">{@code
   * Sec-CH-UA-Platform-Version}</a> header field name.
   *
   * @since 30.0
   */