docs: protected int headerSize(boolean hasrun) {
      if (hasrun) {
        if (size < MutableRoaringArray.NO_OFFSET_THRESHOLD) {// for small bitmaps, we omit the offsets
          return 4 + (size + 7) / 8 + 4 * size;
        }
        return 4 + (size + 7) / 8 + 8 * size;// - 4 because we pack the size with the cookie
      } else {
        return 4 + 4 + 8 * size;
      }
    }