docs: static void checkHeapFlags(final int flags) {  //only used by checkPreLongsFlagsCap and test
      final int allowedFlags =
          READ_ONLY_FLAG_MASK | EMPTY_FLAG_MASK | COMPACT_FLAG_MASK | ORDERED_FLAG_MASK;
      final int flagsMask = ~allowedFlags;
      if ((flags & flagsMask) > 0) {
        throw new SketchesArgumentException(
           "Possible corruption: Invalid flags field: " + Integer.toBinaryString(flags));
      }
    }