public async Task delete_multiple_iotHub_devices()
    {
        DeviceTwinRepository repo = new DeviceTwinRepository(iotHubConnectionString);
        var device1 = await repo.CreateDevice("coffeemaker1");

        var device2 = await repo.CreateDevice("coffeemaker2");

        var device3 = await repo.CreateDevice("coffeemaker3");

        List <string> devices = new List <string> {
            device1.Id, device2.Id, device3.Id
        };
        await repo.DeleteMultipleDevicesAsync(devices);

        var getDevice1 = await repo.GetDevice(device1.Id);

        Assert.Null(getDevice1);
        var getDevice2 = await repo.GetDevice(device2.Id);

        Assert.Null(getDevice2);
        var getDevice3 = await repo.GetDevice(device3.Id);

        Assert.Null(getDevice3);
    }
    public async Task get_iotHub_device()
    {
        DeviceTwinRepository repo = new DeviceTwinRepository(iotHubConnectionString);
        var tags = new DeviceTwinTagsModel()
        {
            ProductFamily    = "ProductFamilyTest",
            ProductName      = "ProductNameTest",
            RetailerName     = "RetailerTest",
            ManufacturedDate = DateTime.Now,
            ShippedDate      = DateTime.Now,
            RetailerRegion   = "Chicago"
        };
        var device = await repo.CreateAndInitializeDeviceTwin("unittestdevice", tags);

        var deviceFound = await repo.GetDevice("unittestdevice");

        Assert.Equal("unittestdevice", deviceFound.Id);
    }