Lucene.Net.Search.SparseFacetedSearcher.SearchInternal C# (CSharp) Method

        private IEnumerable<FacetHits> SearchInternal(Query query = null, int maxDocPerGroup = DefaultMaxDocPerGroup)
        {
            if (query == null)
                query = new MatchAllDocsQuery();

            var queryDocidSet =
                new CachingWrapperFilter(new QueryWrapperFilter(query))
                .GetDocIdSet(reader)
                .AsEnumerable()
                .ToList();

            var hitsPerFacet = groups.Select(g => new FacetHits(g.Item1, reader, queryDocidSet, g.Item2, maxDocPerGroup)).ToList();

            Parallel.ForEach(hitsPerFacet, h => h.Calculate());

            return hitsPerFacet;
        }