@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class RegularImmutableSortedMultiset<E> extends ImmutableSortedMultiset<E> {
  private static final long[] ZERO_CUMULATIVE_COUNTS = {0};

  static final ImmutableSortedMultiset<?> NATURAL_EMPTY_MULTISET =
      new RegularImmutableSortedMultiset<>(Ordering.natural());

  @VisibleForTesting final transient RegularImmutableSortedSet<E> elementSet;