EnumSet<E> set = EnumSet.noneOf(elementType);
    Iterables.addAll(set, iterable);
    return set;
  }

  // HashSet

  /**
   * Creates a <i>mutable</i>, initially empty {@code HashSet} instance.
   *
   * <p><b>Note:</b> if mutability is not required, use {@link ImmutableSet#of()} instead. If {@code

   */
  static int inferDistinctElements(Iterable<?> elements) {
    if (elements instanceof Multiset) {
      return ((Multiset<?>) elements).elementSet().size();
    }
    return 11; // initial capacity will be rounded up to 16
  }

  /**
   * Returns an unmodifiable view of the union of two multisets. In the returned multiset, the count

     * ImmutableSortedMap#orderedBy}.
     */
    public Builder(Comparator<? super K> comparator) {
      this(comparator, ImmutableCollection.Builder.DEFAULT_INITIAL_CAPACITY);
    }

    private Builder(Comparator<? super K> comparator, int initialCapacity) {
      this.comparator = checkNotNull(comparator);
      this.keys = new @Nullable Object[initialCapacity];

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
     * ImmutableMap#builder}.
     */
    public Builder() {
      this(ImmutableCollection.Builder.DEFAULT_INITIAL_CAPACITY);
    }

    @SuppressWarnings({"unchecked", "rawtypes"})
    Builder(int initialCapacity) {
      this.alternatingKeysAndValues = new @Nullable Object[2 * initialCapacity];
      this.size = 0;

  // available.
  /**
   * This field encodes the current state of the future.
   *
   * <p>The valid values are:
   *
   * <ul>
   *   <li>{@code null} initial state, nothing has happened.
   *   <li>{@link Cancellation} terminal state, {@code cancel} was called.
   *   <li>{@link Failure} terminal state, {@code setException} was called.

    int estimatedSize =
        (entries instanceof Collection)
            ? ((Collection<?>) entries).size()
            : ImmutableCollection.Builder.DEFAULT_INITIAL_CAPACITY;
    return new Builder<K, V>(estimatedSize).putAll(entries).build();
  }

  ImmutableBiMap() {}

  /**
   * {@inheritDoc}
   *

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
     * ImmutableSet#builder}.
     */
    public Builder() {
      super(DEFAULT_INITIAL_CAPACITY);
    }

    Builder(int capacity) {
      super(capacity);
      this.hashTable = new @Nullable Object[chooseTableSize(capacity)];
    }

    /**

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
     * ImmutableList#builder}.
     */
    public Builder() {
      this(DEFAULT_INITIAL_CAPACITY);
    }

    Builder(int capacity) {
      super(capacity);
    }

    /**
     * Adds {@code element} to the {@code ImmutableList}.
     *
     * @param element the element to add

      Map<? extends K, ? extends V> map) {
    return new HashMap<>(map);
  }

  /**
   * Creates a {@code HashMap} instance, with a high enough "initial capacity" that it <i>should</i>
   * hold {@code expectedSize} elements without growth. This behavior cannot be broadly guaranteed,
   * but it is observed to be true for OpenJDK 1.7. It also can't be guaranteed that the method

   * avoid memory leaks when an element is no longer necessary.
   *
   * <p>This method accepts an array with element type {@code @Nullable T}, but callers must pass an
   * array whose contents are initially non-null. The {@code @Nullable} annotation indicates that
   * this method will write nulls into the array during iteration.
   *
   * <p>This is mainly just to avoid the intermediate ArrayDeque in ConsumingQueueIterator.