}

  /** Returns the platform preferred implementation of a set based on a hash table. */
  static <E extends @Nullable Object> Set<E> newHashSetWithExpectedSize(int expectedSize) {
    return Sets.newHashSetWithExpectedSize(expectedSize);
  }

  /** Returns the platform preferred implementation of a thread-safe hash set. */
  static <E> Set<E> newConcurrentHashSet() {

    return CompactLinkedHashMap.createWithExpectedSize(expectedSize);
  }

  /** Returns the platform preferred implementation of a set based on a hash table. */
  static <E extends @Nullable Object> Set<E> newHashSetWithExpectedSize(int expectedSize) {
    return CompactHashSet.createWithExpectedSize(expectedSize);
  }

  /**
   * Returns the platform preferred implementation of an insertion ordered set based on a hash
   * table.
   */

    }
  }

  /** An {@code Iterator} over distinct keys in key head order. */
  private final class DistinctKeyIterator implements Iterator<K> {
    final Set<K> seenKeys = Sets.<K>newHashSetWithExpectedSize(keySet().size());
    @Nullable Node<K, V> next = head;
    @Nullable Node<K, V> current;
    int expectedModCount = modCount;

    private void checkForConcurrentModification() {

      checkExactMatches(m, chars);
    }
  }

  static void checkExactMatches(CharMatcher m, char[] chars) {
    Set<Character> positive = Sets.newHashSetWithExpectedSize(chars.length);
    for (char c : chars) {
      positive.add(c);
    }
    for (int c = 0; c <= Character.MAX_VALUE; c++) {

  }

  public void testNewHashSetWithExpectedSizeSmall() {
    HashSet<Integer> set = Sets.newHashSetWithExpectedSize(0);
    verifySetContents(set, EMPTY_COLLECTION);
  }

  public void testNewHashSetWithExpectedSizeLarge() {
    HashSet<Integer> set = Sets.newHashSetWithExpectedSize(1000);
    verifySetContents(set, EMPTY_COLLECTION);
  }

  public void testNewHashSetFromIterator() {

   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call
  public static <E extends @Nullable Object> HashSet<E> newHashSet(E... elements) {
    HashSet<E> set = newHashSetWithExpectedSize(elements.length);
    Collections.addAll(set, elements);
    return set;
  }

  /**
   * Creates a <i>mutable</i> {@code HashSet} instance containing the given elements. A very thin

   * collision rate looks sane.
   */
  static void assertInvariants(HashFunction hashFunction) {
    int objects = 100;
    Set<HashCode> hashcodes = Sets.newHashSetWithExpectedSize(objects);
    Random random = new Random(314159);
    for (int i = 0; i < objects; i++) {
      int value = random.nextInt();
      HashCode hashcode1 = hashFunction.hashInt(value);

            .build(new DelayingIdentityLoader<String>(computationShouldWait, computationLatch));

    int nThreads = 100;
    int nTasks = 1000;
    int nSeededEntries = 100;
    Set<String> expectedKeys = Sets.newHashSetWithExpectedSize(nTasks + nSeededEntries);
    // seed the map, so its segments have a count>0; otherwise, clear() won't visit the in-progress
    // entries
    for (int i = 0; i < nSeededEntries; i++) {
      String s = "b" + i;

            .build(new DelayingIdentityLoader<String>(computationShouldWait, computationLatch));

    int nThreads = 100;
    int nTasks = 1000;
    int nSeededEntries = 100;
    Set<String> expectedKeys = Sets.newHashSetWithExpectedSize(nTasks + nSeededEntries);
    // seed the map, so its segments have a count>0; otherwise, clear() won't visit the in-progress
    // entries
    for (int i = 0; i < nSeededEntries; i++) {
      String s = "b" + i;

    private final Set<Object> delegate;

    JdkBackedSetBuilderImpl(SetBuilderImpl<E> toCopy) {
      super(toCopy); // initializes dedupedElements and distinct
      delegate = Sets.newHashSetWithExpectedSize(distinct);
      for (int i = 0; i < distinct; i++) {
        /*
         * requireNonNull is safe because we ensure that the first `distinct` elements have been
         * populated.
         */