var loader = tradeService.All
    .Connect(trade => trade.Status == TradeStatus.Live) //prefilter live trades only
    .Filter(_filter) // apply user filter
    .Transform(trade => new TradeProxy(trade),new ParallelisationOptions(ParallelType.Ordered,5))
    .Sort(SortExpressionComparer<TradeProxy>.Descending(t => t.Timestamp),SortOptimisations.ComparesImmutableValuesOnly)
    .ObserveOnDispatcher()
    .Bind(_data)   // update observable collection bindings
    .DisposeMany() //since TradeProxy is disposable dispose when no longer required
    .Subscribe();

var loader = tradeService.Live.Connect()
           .Group(trade => trade.CurrencyPair)
           .Transform(group => new CurrencyPairPosition(group))
           .Sort(SortExpressionComparer<CurrencyPairPosition>.Ascending(t => t.CurrencyPair))
           .ObserveOn(schedulerProvider.MainThread)
           .Bind(_data)
           .DisposeMany()
           .Subscribe();

   //when CurrencyPairPosition class does this
   tradesByCurrencyPair.Cache.Connect()
   		.QueryWhenChanged(query =>
   		{
   			var buy = query.Items.Where(trade => trade.BuyOrSell == BuyOrSell.Buy).Sum(trade=>trade.Amount);
   			var sell = query.Items.Where(trade => trade.BuyOrSell == BuyOrSell.Sell).Sum(trade => trade.Amount);
   			var count = query.Count;
   			return new TradesPosition(buy,sell,count);
   		})
   		.Subscribe(position => Position = position);
       }