public static <E> ImmutableSet<E> copyOf(Iterable<? extends E> elements) {
    if (elements instanceof ImmutableSet && !(elements instanceof ImmutableSortedSet)) {
      @SuppressWarnings("unchecked") // all supported methods are covariant
      ImmutableSet<E> set = (ImmutableSet<E>) elements;
      return set;
    }
    return copyOf(elements.iterator());
  }

  public static <E> ImmutableSet<E> copyOf(Iterator<? extends E> elements) {

  }

  @Override
  public T or(T defaultValue) {
    return checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
  }

  @SuppressWarnings("unchecked") // safe covariant cast
  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    return (Optional<T>) checkNotNull(secondChoice);
  }

  @Override
  public T or(Supplier<? extends T> supplier) {

   * already been re-added.
   */
  // Technically should accept RemovalNotification<? extends K, ? extends V>, but because
  // RemovalNotification is guaranteed covariant, let's make users' lives simpler.
  void onRemoval(RemovalNotification<K, V> notification);

       * TODO: When given an ImmutableList that's a sublist, copy the referenced
       * portion of the array into a new array to save space?
       */
      @SuppressWarnings("unchecked") // all supported methods are covariant
      ImmutableCollection<E> list = (ImmutableCollection<E>) elements;
      return list.asList();
    }
    return copyFromCollection(elements);
  }

  @JsMethod

    UnmodifiableTable(Table<? extends R, ? extends C, ? extends V> delegate) {
      this.delegate = checkNotNull(delegate);
    }

    @SuppressWarnings("unchecked") // safe, covariant cast
    @Override
    protected Table<R, C, V> delegate() {
      return (Table<R, C, V>) delegate;
    }

    @Override
    public Set<Cell<R, C, V>> cellSet() {

   */
  public static <E> ImmutableList<E> copyOf(Collection<? extends E> elements) {
    if (elements instanceof ImmutableCollection) {
      @SuppressWarnings("unchecked") // all supported methods are covariant
      ImmutableList<E> list = ((ImmutableCollection<E>) elements).asList();
      return list.isPartialView() ? ImmutableList.<E>asImmutableList(list.toArray()) : list;
    }
    return construct(elements.toArray());

    if (map instanceof ImmutableClassToInstanceMap) {
      @SuppressWarnings("rawtypes") // JDT-based J2KT Java frontend does not permit the direct cast
      Map rawMap = map;
      @SuppressWarnings("unchecked") // covariant casts safe (unmodifiable)
      ImmutableClassToInstanceMap<B> cast = (ImmutableClassToInstanceMap<B>) rawMap;
      return cast;
    }
    return new Builder<B>().putAll(map).build();
  }

  }

  /**
   * Returns the empty immutable multiset.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked") // all supported methods are covariant
  public static <E> ImmutableMultiset<E> of() {
    return (ImmutableMultiset<E>) RegularImmutableMultiset.EMPTY;
  }

  /**
   * Returns an immutable multiset containing a single element.
   *

@Suppress("UNCHECKED_CAST")
internal fun <T> List<T>.toImmutableList(): List<T> =
  when {
    this.isEmpty() -> emptyList()
    this.size == 1 -> Collections.singletonList(this[0])
    // Collection.toArray returns Object[] (covariant).
    // It is faster than creating real T[] via reflection (Arrays.copyOf).
    else -> (this as java.util.Collection<*>).toArray().asList().unmodifiable() as List<T>
  }

        checkNotNull(cell.getRowKey(), "row");
        checkNotNull(cell.getColumnKey(), "column");
        checkNotNull(cell.getValue(), "value");
        @SuppressWarnings("unchecked") // all supported methods are covariant
        Cell<R, C, V> immutableCell = (Cell<R, C, V>) cell;
        cells.add(immutableCell);
      } else {
        put(cell.getRowKey(), cell.getColumnKey(), cell.getValue());
      }
      return this;