public Result clone() {
        Result resultClone = (Result) super.clone();

        resultClone.hits = hits.clone();

        resultClone.setElapsedTime(new ElapsedTime());
        return resultClone;
    }
Deep clones this result - copies are made of all hits and subgroups of hits,
<i>but not of the query referenced by this</i>.
container-search/src/main/java/com/yahoo/search/Result.java