tx.cs

using (HttpClient client = CreateHttpClient())
{
    // set the endpoint
    HttpResponseMessage response = client.GetAsync("api.rsc/Customer").Result;

    // return an ActionSettings object, if sucessful
    if (response.IsSuccessStatusCode)
    {
        string result = await response.Content.ReadAsStringAsync();

        List<Customer> customers = 
            JObject.Parse(result)["value"].ToObject<List<Customer>>();

        Report report = new Report()
        {
            Customers = customers
        };

        ReportingCloud rc = new ReportingCloud(
            "username", 
            "password", 
            new Uri("https://api.reporting.cloud"));

        MergeBody mergeBody = new MergeBody() {
            MergeData = report
        };

        List<string> results = rc.MergeDocument(
            mergeBody, "CloudDriver_Sample.tx");
        File.WriteAllBytes("results.pdf", Convert.FromBase64String(results[0]));
    }
    else
    {
        // throw exception with the message from the endpoint
        throw new ArgumentException(response.Content.ReadAsStringAsync().Result);
    }
}