// if checkTime, we want to check *after* acquiring the lock if refresh still needs
              // to be scheduled
              return null;
            }

            // continue returning old value while loading
            ++modCount;
            LoadingValueReference<K, V> loadingValueReference =
                new LoadingValueReference<>(valueReference);

   * possible pair of these futures in {@link FuturesTest#runExtensiveMergerTest}.
   *
   * <p>Each test requires a new {@link TestFutureBatch} because we need new delayed futures each
   * time, as the old delayed futures were completed as part of the old test.
   */
  @J2ktIncompatible
  @GwtIncompatible // used only in GwtIncompatible tests
  private static final class TestFutureBatch {

   * possible pair of these futures in {@link FuturesTest#runExtensiveMergerTest}.
   *
   * <p>Each test requires a new {@link TestFutureBatch} because we need new delayed futures each
   * time, as the old delayed futures were completed as part of the old test.
   */
  @J2ktIncompatible
  @GwtIncompatible // used only in GwtIncompatible tests
  private static final class TestFutureBatch {

              // if checkTime, we want to check *after* acquiring the lock if refresh still needs
              // to be scheduled
              return null;
            }

            // continue returning old value while loading
            ++modCount;
            LoadingValueReference<K, V> loadingValueReference =
                new LoadingValueReference<>(valueReference);

   * normally derive from {@code Map<Object, Object>}, but they typically contain strings, which is
   * awkward. This method lets you get a plain-old-{@code Map} out of a {@code Properties}.
   *
   * @param properties a {@code Properties} object to be converted
   * @return an immutable map containing all the entries in {@code properties}