documentContent is required, but it shouldn't be

[JamesPaden]

I have to include a blank documentContent line, or an error is thrown :( it should be optional if I use documentUrl

using DocRaptor.Client;
using DocRaptor.Model;
using DocRaptor.Api;
using System;
using System.IO;

class Example
{
    static void Main(string[] args)
    {
        DocApi docraptor = new DocApi();
        // this key works in test mode!
        docraptor.Configuration.Username = "YOUR_API_KEY_HERE";

        try
        {
            Doc doc = new Doc(
                name: "invoice",
                test: true, // test documents are free but watermarked
                documentType: Doc.DocumentTypeEnum.Pdf,
                documentContent: "", // the .NET agent requires documentContent be set
                documentUrl: "https://docraptor.com/samples/invoice.html" 
                // javascript: false, 
            );

            byte[] pdf = docraptor.CreateDoc(doc);
            File.WriteAllBytes("invoice.pdf", pdf);
            Console.WriteLine("Successfully created invoice.pdf!");
        } catch (DocRaptor.Client.ApiException error) {
            Console.Write(error.ErrorContent);
        }
    }
}