* (is a subtype of) {@code clazz}. Example:
   *
   * <pre>{@code
   * List<Class<?>> classes = Arrays.asList(
   *     Object.class, String.class, Number.class, Long.class);
   * return Iterables.filter(classes, subtypeOf(Number.class));
   * }</pre>
   *
   * The code above returns an iterable containing {@code Number.class} and {@code Long.class}.
   *

   * (is a subtype of) {@code clazz}. Example:
   *
   * <pre>{@code
   * List<Class<?>> classes = Arrays.asList(
   *     Object.class, String.class, Number.class, Long.class);
   * return Iterables.filter(classes, subtypeOf(Number.class));
   * }</pre>
   *
   * The code above returns an iterable containing {@code Number.class} and {@code Long.class}.
   *