public async Task CheckComplOrders() { var deleted = new List <Seller>(); foreach (Seller seller in Sellers) { if (await seller.IsCpmplited()) { deleted.Add(seller); Complited.Add(seller); } } foreach (Seller seller in deleted) { Sellers.Remove(seller); } if (await Buyer.IsComplited()) { var complitedOrder = Buyer.PopComplited(); if (complitedOrder != null) { Sellers.Add(new Seller(complitedOrder, Tracker.Sett.Delta, _market.Api)); } } }