*
   * @return null if an explanation cannot be provided (e.g. because the future is done).
   * @since 23.0
   */
  @CheckForNull
  protected String pendingToString() {
    // TODO(diamondm) consider moving this into addPendingString so it's always in the output
    if (this instanceof ScheduledFuture) {
      return "remaining delay=["
          + ((ScheduledFuture) this).getDelay(TimeUnit.MILLISECONDS)
          + " ms]";

 * }</pre>
 *
 * <p>so that a hypothetical bad caller of this method, such as:
 *
 * <pre>{@code
 * void exampleBadCaller() {
 *   double d = sqrt(-1.0);
 * }
 * }</pre>
 *
 * <p>would be flagged as having called {@code sqrt()} with an illegal argument.
 *
 * <h3>Performance</h3>
 *
 * <p>Avoid passing message arguments that are expensive to compute; your code will always compute

 * }</pre>
 *
 * <p>so that a hypothetical bad caller of this method, such as:
 *
 * <pre>{@code
 * void exampleBadCaller() {
 *   double d = sqrt(-1.0);
 * }
 * }</pre>
 *
 * <p>would be flagged as having called {@code sqrt()} with an illegal argument.
 *
 * <h3>Performance</h3>
 *
 * <p>Avoid passing message arguments that are expensive to compute; your code will always compute

   * any of the provided futures fails or is canceled, its corresponding position will contain
   * {@code null} (which is indistinguishable from the future having a successful value of {@code
   * null}).
   *
   * <p>The list of results is in the same order as the input list.
   *
   * <p>This differs from {@link #allAsList(ListenableFuture[])} in that it's tolerant of failed

  }

  /**
   * Sets the minimum total size for the internal hash tables. For example, if the initial capacity
   * is {@code 60}, and the concurrency level is {@code 8}, then eight segments are created, each
   * having a hash table of size eight. Providing a large enough estimate at construction time
   * avoids the need for expensive resizing operations later, but setting this value unnecessarily
   * high wastes memory.
   *

   *
   * <p>It appears that properly handling recursive type bounds in the presence of implicit type
   * bounds is not easy. For now we punt, hoping that this defect should rarely cause issues in real
   * code.
   *
   * @param formalType is {@code Foo<formalType>} a supertype of {@code Foo<T>}?