docs: PairTable rebuild(final int newLgSizeInts) {
      checkLgSizeInts(newLgSizeInts);
      final int newSize = 1 << newLgSizeInts;
      final int oldSize = 1 << lgSizeInts;
      rtAssert(newSize > numPairs);
      final int[] oldSlotsArr = slotsArr;
      slotsArr = new int[newSize];
      Arrays.fill(slotsArr, -1);
      lgSizeInts = newLgSizeInts;
      for (int i = 0; i < oldSize; i++) {
        final int item = oldSlotsArr[i];
        if (item != -1) { mustInsert(this, item); }
      }
      return this;
    }