I don't believe all the code in DocumentGenerator.cs is behaving as expected. The below methods (lines 117-129) are adding blank pages to the generated pdf.
private static void EmbedFileStream(RadFixedDocument document, string filePath, string name)
{
RadFixedPage page = document.Pages.AddPage();
byte[] textFile = File.ReadAllBytes(filePath);
document.EmbeddedFiles.Add(name, textFile);
}
private static void AddZugferdInvoice(RadFixedDocument document, string invoicePath)
{
byte[] bytes = File.ReadAllBytes(invoicePath);
//Only a single XML invoice attachment is allowed according to ZUGFeRD standard.
document.EmbeddedFiles.AddZugferdInvoice(bytes);
}