@Override
    public void copyRange(LongArray src, int srcPos, LongArray dst, int dstPos, int length) {
        Platform.copyMemory(
                src.getBaseObject(),
                src.getBaseOffset() + srcPos * 16,
                dst.getBaseObject(),
                dst.getBaseOffset() + dstPos * 16,
                length * 16);
    }
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