private void addResultsToFill(HitGroup hitGroup, Result result, String summaryClass,
                                  UniqueExecutionsToResults uniqueExecutionsToResults) {
        for (Hit hit : hitGroup) {
            if (hit instanceof HitGroup) {
                addResultsToFill((HitGroup) hit, result, summaryClass, uniqueExecutionsToResults);
            } else {
                if ( ! hit.isFilled(summaryClass))
                    getSearchChainGroup(hit, result, uniqueExecutionsToResults).hits().add(hit);
            }
        }
    }
The name of the query property containing the source name added to the query to each source by this
container-search/src/main/java/com/yahoo/search/federation/FederationSearcher.java