* eagerly initialized.
   */
  private static final class CompactStriped<L> extends PowerOfTwoStriped<L> {
    /** Size is a power of two. */
    private final Object[] array;

    private CompactStriped(int stripes, Supplier<L> supplier) {
      super(stripes);
      Preconditions.checkArgument(stripes <= Ints.MAX_POWER_OF_TWO, "Stripes must be <= 2^30)");