* equivalent to RegularImmutableSet, save that instead of having a hash table containing the
   * elements directly and null for empty positions, we store indices of the keys in the hash table,
   * and ABSENT for empty positions.  We then look up the keys in alternatingKeysAndValues.
   *
   * (The index actually stored is the index of the key in alternatingKeysAndValues, which is
   * double the index of the entry in entrySet.asList.)
   *

   * specified function to each item in an {@code Iterable} of values. Each value will be stored as
   * a value in the resulting multimap, yielding a multimap with the same size as the input
   * iterable. The key used to store that value in the multimap will be the result of calling the
   * function on that value. The resulting multimap is created as an immutable snapshot. In the

  //   completion preferably and AQS is non-deterministic (depends on where in the queue the waiter
  //   is). If we wanted to be strict about it, we could store the unpark() time in the Waiter node
  //   and we could use that to make a decision about whether or not we timed out prior to being
  //   unparked.

  /**
   * {@inheritDoc}
   *

     * based on the first time it was added, again unless {@link #orderEntriesByValue} was called.
     *
     * <p>In the current implementation, all values associated with a given key are stored in the
     * {@code Builder} object, even though only one of them will be used in the built map. If there
     * can be many repeated keys, it may be more space-efficient to use a {@link

   * element, in order to determine the element type. If the collection could be empty, use {@link
   * #complementOf(Collection, Class)} instead of this method.
   *
   * @param collection the collection whose complement should be stored in the enum set
   * @return a new, modifiable {@code EnumSet} containing all values of the enum that aren't present
   *     in the given collection

      while (elements.hasNext()) {
        add(elements.next());
      }
      return this;
    }

    @CanIgnoreReturnValue
    @SuppressWarnings("unchecked") // ArrayBasedBuilder stores its elements as Object.
    Builder<E> combine(Builder<E> other) {
      if (hashTable != null) {
        for (int i = 0; i < other.size; ++i) {

    checkNotNull(iterable);
    return new Iterator<T>() {
      Iterator<T> iterator = emptyModifiableIterator();

      @Override
      public boolean hasNext() {
        /*
         * Don't store a new Iterator until we know the user can't remove() the last returned
         * element anymore. Otherwise, when we remove from the old iterator, we may be invalidating