public void mergeWith(Result result) {
        totalHitCount += result.getTotalHitCount();
        deepHitCount += result.getDeepHitCount();
        timeAccountant.merge(result.getElapsedTime());
        boolean create = true;
        if (result.getCoverage(!create) != null || getCoverage(!create) != null)
            getCoverage(create).merge(result.getCoverage(create));
    }
Merges <b>meta information</b> from a result into this.
This does not merge hits, but the other information associated
with a result. It should <b>always</b> be called when adding
hits from a result, but there is no constraints on the order of the calls.
container-search/src/main/java/com/yahoo/search/Result.java