applyMask

Apply this Bits instance to the given FixedBitSet, which starts at the given offset.

This should behave the same way as the default implementation, which does the following:

for (int i = bitSet.nextSetBit(0);
i != DocIdSetIterator.NO_MORE_DOCS;
i = i + 1 >= bitSet.length() ? DocIdSetIterator.NO_MORE_DOCS : bitSet.nextSetBit(i + 1)) {
if (get(offset + i) == false) {
bitSet.clear(i);
}
}