docs: public int numberOfRunsLowerBound(int mustNotExceed) {
      int numRuns = 0;
  
      for (int blockOffset = 0; blockOffset < bitmap.length; blockOffset += BLOCKSIZE) {
  
        for (int i = blockOffset; i < blockOffset + BLOCKSIZE; i++) {
          long word = bitmap[i];
          numRuns += Long.bitCount((~word) & (word << 1));
        }
        if (numRuns > mustNotExceed) {
          return numRuns;
        }
      }
      return numRuns;
    }