*
   * <p><b>Note:</b> on Java 8+, it is usually better to use streams. For example:
   *
   * <pre>{@code
   * import static com.google.common.collect.ImmutableMap.toImmutableMap;
   * ...
   * ImmutableMap<String, Color> colorForName =
   *     allColors.stream().collect(toImmutableMap(c -> c.toString(), c -> c));
   * }</pre>
   *

   *       {@link #withoutCloser(AsyncFunction)}
   * </ul>
   *
   * <p>Example usage:
   *
   * <pre>{@code
   * // Fall back to a secondary input stream in case of IOException.
   * ClosingFuture<InputStream> inputFuture =
   *     firstInputFuture.catchingAsync(
   *         IOException.class, (closer, x) -> secondaryInputStreamClosingFuture(), executor);
   * }