How to add file attachment to PDF document from buffer into PDF generated with Bytescout.PDF library for .NET

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using Bytescout.PDF;

namespace DemoProject
{
class Program
{
static void Main(string[] args)
{
// Create main PDF Doc Engine
PDFDocEngine engine = new PDFDocEngine("demo", "demo");
// Add new document
Document document = engine.AddDocument();
// Append new page to the document
Page page = document.AddPage(PageSizeType.A3, PageOrientationType.LandScape);
// Marshal.Copy();
byte[] documentToAttach = File.ReadAllBytes("HelloWorld.pdf");
document.AddAttachedFileFromBuffer(documentToAttach, (uint)documentToAttach.Length, "HelloWorld.pdf", "HelloWorld", false);
// Save document
document.Save("AddAttachedFileFromBuffer.pdf");
}
}
}

Download example source code: bytescoutpdf_add_file_attachment_from_buffer.zip (4 KB)