Add file attachment (embedded attachment) to PDF document generated with ByteScout PDF SDK

How to embedded add file attachment into PDF document using ByteScout PDF SDK
The example demonstrates how to attach a file to PDF document using ByteScout PDF SDK.

Program.vb:
VB

'*******************************************************************
'       ByteScout PDF SDK
'                                                                   
'       Copyright © 2016 Bytescout, https://bytescout.com        
'       ALL RIGHTS RESERVED                                         
'                                                                   
'*******************************************************************

Imports Bytescout.PDF

''' <summary>
''' This example demonstrates how to attach a file to PDF document.
''' </summary>
Class Program

    Shared Sub Main()

        ' Create new document
        Dim pdfDocument = New Document()
        pdfDocument.RegistrationName = "demo"
		pdfDocument.RegistrationKey = "demo"
        ' Add page
        Dim page = New Page(PaperFormat.A4)
        pdfDocument.Pages.Add(page)

        ' Attach file
        Dim fileAttachment = New FileAttachmentAnnotation("sample_attachment.txt", 20, 20, 20, 20)
        fileAttachment.Icon = FileAttachmentAnnotationIcon.Paperclip
        page.Annotations.Add(fileAttachment)

        ' Instruct PDF viewer application to show attachments pane on startup
        pdfDocument.PageMode = PageMode.Attachment

        ' Save document to file
        pdfDocument.Save("result.pdf")

        ' Cleanup 
		pdfDocument.Dispose()

        ' Open document in default PDF viewer app
        Process.Start("result.pdf")

    End Sub

End Class 

Program.cs:
C#

//*******************************************************************
//       ByteScout PDF SDK		                                     
//                                                                   
//       Copyright © 2016 ByteScout - https://bytescout.com       
//       ALL RIGHTS RESERVED                                         
//                                                                   
//*******************************************************************

using System.Diagnostics;
using Bytescout.PDF;

namespace FileAttachmentAnnotationExample
{
	/// <summary>
	/// This example demonstrates how to attach a file to PDF document.
	/// </summary>
	class Program
	{
		static void Main()
		{
			// Create new document
			Document pdfDocument = new Document();
			pdfDocument.RegistrationName = "demo";
			pdfDocument.RegistrationKey = "demo";
			// Add page
			Page page = new Page(PaperFormat.A4);
			pdfDocument.Pages.Add(page);

			// Attach file
			FileAttachmentAnnotation fileAttachment = new FileAttachmentAnnotation("sample_attachment.txt", 20, 20, 20, 20);
			fileAttachment.Icon = FileAttachmentAnnotationIcon.Paperclip;
			page.Annotations.Add(fileAttachment);
			
			// Instruct PDF viewer application to show attachments pane on startup
			pdfDocument.PageMode = PageMode.Attachment;
			
			// Save document to file
			pdfDocument.Save("result.pdf");

			// Cleanup 
			pdfDocument.Dispose();

			// Open document in default PDF viewer app
			Process.Start("result.pdf");
		}
	}
}