public static <X> void save(final IntSet x, final DataOutput out) {
    try {
      DataInputOutputUtil.writeINT(out, x.size());
      x.forEach(value -> {
        try {
          DataInputOutputUtil.writeINT(out, value);
        }
        catch (IOException e) {
          throw new BuildDataCorruptedException(e);
        }
      });
    }
    catch (IOException c) {
      throw new BuildDataCorruptedException(c);
    }
  }
public static <X> void save(final IntSet x, final DataOutput out)