return of();
    } else {
      return lazyComplement();
    }
  }

  @LazyInit @RetainedWith private transient @Nullable ImmutableRangeSet<C> lazyComplement;

  private ImmutableRangeSet<C> lazyComplement() {
    ImmutableRangeSet<C> result = lazyComplement;
    return result == null
        ? lazyComplement =