private static void AddPackagesToIndex(List<IndexDocumentData> indexDocumentData, Lucene.Net.Store.Directory directory, TextWriter log, PerfEventTracker perfTracker)
        {
            log.WriteLine("About to add {0} packages", indexDocumentData.Count);

            for (int index = 0; index < indexDocumentData.Count; index += MaxDocumentsPerCommit)
            {
                int count = Math.Min(MaxDocumentsPerCommit, indexDocumentData.Count - index);

                List<IndexDocumentData> rangeToIndex = indexDocumentData.GetRange(index, count);

                AddToIndex(directory, rangeToIndex, log, perfTracker);
            }
        }