@ElementTypesAreNonnullByDefault
final class NaturalOrdering extends Ordering<Comparable<?>> implements Serializable {
  static final NaturalOrdering INSTANCE = new NaturalOrdering();

  // TODO: b/287198172 - Consider eagerly initializing these (but think about serialization).
  @LazyInit @CheckForNull private transient Ordering<@Nullable Comparable<?>> nullsFirst;
  @LazyInit @CheckForNull private transient Ordering<@Nullable Comparable<?>> nullsLast;