public async Task Execute(AddSalesOrderLineCommand command)
        {
            var message = new AddSalesOrderLineMessage(command.SalesOrderKey, command.ProductKey, command.Quantity, command.Price);

            var salesOrderGrain = GrainFactory.GetGrain <ISalesOrderGrain>(command.SalesOrderKey);

            await salesOrderGrain.AddLine(message);
        }
        public Task AddLine(AddSalesOrderLineMessage message)
        {
            var line = new SalesOrderLine(message.ProductKey, message.Quantity, message.Price, message.Comment);

            _salesOrder.AddLine(line);

            return(TaskDone.Done);
        }