@Override
    public void swap(LongArray data, int pos0, int pos1) {
        long tempPointer = data.get(pos0 * 2);
        long tempKeyPrefix = data.get(pos0 * 2 + 1);
        data.set(pos0 * 2, data.get(pos1 * 2));
        data.set(pos0 * 2 + 1, data.get(pos1 * 2 + 1));
        data.set(pos1 * 2, tempPointer);
        data.set(pos1 * 2 + 1, tempKeyPrefix);
    }
Supports sorting an array of (record pointer, key prefix) pairs.
Used in {@link UnsafeInMemorySorter}.

Within each long[] buffer, position {@code 2 * i} holds a pointer pointer to the record at
index {@code i}, while position {@code 2 * i + 1} in the array holds an 8-byte key prefix.
indexr-query-opt/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeSortDataFormat.java