private async Task UpdateHubOverview(Order order, WarehouseProjection projection)
        {
            if (projection.orderNumbers.Contains(order.orderNumber))
            {
                return;
            }

            ++projection.count;
            projection.orderNumbers.Add(order.orderNumber);

            await _warehouseViewRepository.UpdateDocument(projection);
        }
        private async Task CreateHubOverview(Order order,
                                             string partitionKey)
        {
            WarehouseProjection projection;

            projection = new WarehouseProjection
            {
                hubId        = order.hubId,
                count        = 1,
                partitionKey = partitionKey,
                orderNumbers = new List <string> {
                    order.orderNumber
                }
            };

            await _warehouseViewRepository.CreateDocument(projection);
        }