docs: private boolean initializeSearchItemset(BitVector bv, int[] scratchi, int[] iters) {
      for(int i = 0; i < scratchi.length; i++) {
        iters[i] = (i == 0) ? bv.iter() : bv.iterAdvance(iters[i - 1]);
        if(iters[i] < 0) {
          return false;
        }
        scratchi[i] = bv.iterDim(iters[i]);
      }
      return true;
    }