public MergedIndex(IPackageSearchMetadataSplicer splicer)
            {
                if (splicer == null)
                {
                    throw new ArgumentNullException(nameof(splicer));
                }

                _splicer = splicer;
            }
        public SearchResultsAggregator(ISearchResultsIndexer indexer, IPackageSearchMetadataSplicer splicer)
        {
            if (indexer == null)
            {
                throw new ArgumentNullException(nameof(indexer));
            }

            _indexer = indexer;

            if (splicer == null)
            {
                throw new ArgumentNullException(nameof(splicer));
            }

            _splicer = splicer;
        }