public int DeleteMany(string collection, BsonExpression predicate)
 {
     try
     {
         NotificationService.Cache.AddBroadcast(collection);
         var result = _engine.DeleteMany(collection, predicate);
         NotificationService.Notify();
         return(result);
     }
     catch (Exception ex)
     {
         throw ex;
     }
     finally
     {
         NotificationService.Clear();
     }
 }