* setException() will be a no-op because the Future is already done.
     *
     * Both scenarios are bad: The output Future might never complete, or, if it does complete, it
     * might not run some of its listeners. The likely result is that the app will hang. (And of
     * course stack overflows are bad news in general. For example, we may have overflowed in the

    if (supportsRemove) {
      // We use a copy of "entryToRemove" in the assertion because "entryToRemove" might be
      // invalidated and have undefined behavior after entrySet.removeAll(entriesToRemove),
      // for example entryToRemove.getValue() might be null.
      Entry<K, V> entryToRemoveCopy =
          Helpers.mapEntry(entryToRemove.getKey(), entryToRemove.getValue());

   * remove elements later. Otherwise, for non-null elements use {@link ImmutableList#of()} (for
   * varargs) or {@link ImmutableList#copyOf(Object[])} (for an array) instead. If any elements
   * might be null, or you need support for {@link List#set(int, Object)}, use {@link
   * Arrays#asList}.
   *
   * <p>Note that even when you do need the ability to add or remove, this method provides only a

      this.comparator = checkNotNull(comparator);
    }

    /**
     * Associates {@code key} with {@code value} in the built map. Duplicate keys, according to the
     * comparator (which might be the keys' natural order), are not allowed, and will cause {@link
     * #build} to fail.
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> put(K key, V value) {
      super.put(key, value);

 *
 * <p>A non-null {@code Optional<T>} reference can be used as a replacement for a nullable {@code T}
 * reference. It allows you to represent "a {@code T} that must be present" and a "a {@code T} that
 * might be absent" as two distinct types in your program, which can aid clarity.
 *
 * <p>Some uses of this class include
 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no

    builder.put("d", 2);
    builder.put("a", 5);
    builder.orderKeysBy(
        new Ordering<String>() {
          @Override
          public int compare(String left, String right) {
            return left.length() - right.length();
          }
        });
    builder.put("cc", 4);
    builder.put("a", 2);
    builder.put("bb", 6);
    ImmutableSetMultimap<String, Integer> multimap = builder.build();

  int hashCode();

  /**
   * Returns a readable string representation of this range set. For example, if this {@code
   * RangeSet} consisted of {@code Range.closed(1, 3)} and {@code Range.greaterThan(4)}, this might
   * return {@code " [1..3](4..+∞)}"}.
   */
  @Override
  String toString();

    return new SingletonImmutableSet<>(element);
  }

  /*
   * TODO: b/315526394 - Skip the Builder entirely for the of(...) methods, since we don't need to
   * worry that we might trigger the fallback to the JDK-backed implementation? (The varargs one
   * _could_, so we could keep it as it is. Or we could convince ourselves that hash flooding is
   * unlikely in practice there, too.)
   */

  /**

         *
         * Sun bug 6665356 is an additional complication. Until OpenJDK 7, javac
         * doesn't recognize this kind of cast as unchecked cast. Neither does
         * Eclipse 3.4. Right now, this suppression is mostly unnecessary.
         */
        @SuppressWarnings("unchecked")
        MultiExceptionListIterator multiExceptionListIterator =
            (MultiExceptionListIterator) reference;

    // then we know it must have given a pending toString value earlier. If not, then the future
    // completed after the timeout expired, and the message might be success.
    if (isDone()) {
      throw new TimeoutException(message + " but future completed as timeout expired");
    }
    throw new TimeoutException(message + " for " + futureToString);
  }

  /**