public void GlobalCleanupNormal()
        {
            _fileMetaNormalCollection = null;

            DatabaseInstanceNormal.DropCollection(nameof(FileMetaBase));
            DatabaseInstanceNormal.Dispose();
        }
        public void CleanUpNormal()
        {
            const string collectionName = nameof(FileMetaBase);

            var droppedCollectionIndexes = DatabaseInstanceNormal.GetCollection(collectionName).GetIndexes().ToList();

            DatabaseInstanceNormal.DropCollection(collectionName);

            foreach (var indexInfo in droppedCollectionIndexes)
            {
                DatabaseInstanceNormal.Engine.EnsureIndex(collectionName, indexInfo.Field, indexInfo.Expression);
            }
        }