public static HitGroup createAsync(String id) {
        DefaultIncomingData<Hit> incomingData = new DefaultIncomingData<>();
        HitGroup hitGroup = new HitGroup(id, new Relevance(1), incomingData);
        incomingData.assignOwner(hitGroup);
        return hitGroup;
    }
Creates a HitGroup which contains data which arrives in the future.

@param id the id of this
@return a HitGroup which is incomplete and which has an {@link #incoming} where new hits can be added later
container-search/src/main/java/com/yahoo/search/result/HitGroup.java