public void fill(Result result, String summaryClass) {
        if (result.isFilled(summaryClass)) return; // TODO: Checked in the superclass - remove

        List<Result> parts = partitionHits(result, summaryClass);
        if (!parts.isEmpty()) { // anything to fill at all?
            for (Result r : parts) {
                doPartialFill(r, ensureLegalSummaryClass(r.getQuery(), summaryClass));
                mergeErrorsInto(result, r);
            }
            result.hits().setSorted(false);
            result.analyzeHits();
        }
    }
Returns whether we need to send the query when fetching summaries.
This is necessary if the query requests summary features or dynamic snippeting.
container-search/src/main/java/com/yahoo/prelude/fastsearch/VespaBackend.java