How to Fix Thread Being Aborted when Saving ASP.NET Web Forms PDF?

if (fileName == null)
{
    throw new ArgumentNullException("fileName");
}
if (response == null)
{
    throw new ArgumentNullException("response");
}
response.ClearContent();
response.Expires = 0;
response.Buffer = true;
string disposition = "content-disposition";
if (type == HttpReadType.Open)
{
    response.AddHeader(disposition, "inline; filename=" + fileName);
}
else if (type == HttpReadType.Save)
{
    response.AddHeader(disposition, "attachment; filename=" + fileName);
}
response.AddHeader("Content-Type", "application/pdf");
response.Clear();
Save(response.OutputStream);
if (PdfDocumentBase.IsSecurityGranted)
{
    response.Flush();
    response.End();
}
else
{
    response.End();
}

using Syncfusion.Pdf.Parsing;
using System.IO;

Imports Syncfusion.Pdf.Parsing
Imports System.IO

protected void OnButtonClicked(object sender, EventArgs e)
{
    //Get input PDF file path
    string file = GetFilePath("Input.pdf");
    //Get byte array from input file
    var byteArray = GetBytesFromFile(file);
    //Load an existing PDF
    PdfLoadedDocument doc = new PdfLoadedDocument(byteArray, true);
    //Save the document into the HTTP response stream
    doc.Save(string.Format("Sample.pdf"), HttpContext.Current.Response, Syncfusion.Pdf.HttpReadType.Save);
    //Open the PDF document
    System.Diagnostics.Process.Start("Sample.pdf");
}
//Helps to get byte array from input file
public byte[] GetBytesFromFile(string fullFilePath)
{
    FileStream fs = File.OpenRead(fullFilePath);
    try
    {
        byte[] bytes = new byte[fs.Length];
        fs.Read(bytes, 0, Convert.ToInt32(fs.Length));
        fs.Close();
        return bytes;
    }
    finally
    {
        fs.Close();
    }
}
//Helps to get physical application path of input file
public string GetFilePath(string path)
{
    string _dataPath = GetCommonFolder(new DirectoryInfo(HttpContext.Current.Request.PhysicalApplicationPath));
    _dataPath += @"\" + path;
    return _dataPath;
}
//Helps to get physical application path of output file
static string GetCommonFolder(DirectoryInfo dtInfo)
{
    var _folderNames = dtInfo.GetDirectories("Data");
    if (_folderNames.Length > 0)
    {
        return _folderNames[0].FullName;
    }
    return dtInfo.Parent != null ? GetCommonFolder(dtInfo.Parent) : string.Empty;
}

Protected Sub OnButtonClicked(sender As Object, e As EventArgs)
    'Get input PDF file path
    Dim file As String = GetFilePath("Input.pdf")
    'Get byte array from input file
    Dim byteArray = GetBytesFromFile(file)
    'Load an existing PDF
    Dim doc As New PdfLoadedDocument(byteArray, True)
    'Save the document into the HTTP response stream
    doc.Save(String.Format("Sample.pdf"), HttpContext.Current.Response, Syncfusion.Pdf.HttpReadType.Save)
    'Open the PDF document
    System.Diagnostics.Process.Start("Sample.pdf")
End Sub
'Helps to get byte array from input file
Public Function GetBytesFromFile(fullFilePath As String) As Byte()
    Dim fs As FileStream = File.OpenRead(fullFilePath)
    Try
        Dim bytes As Byte() = New Byte(fs.Length - 1) {}
        fs.Read(bytes, 0, Convert.ToInt32(fs.Length))
        fs.Close()
        Return bytes
     Finally
         fs.Close()
     End Try
End Function
'Helps to get physical application path of input file
Public Function GetFilePath(path As String) As String
    Dim _dataPath As String = GetCommonFolder(New DirectoryInfo(HttpContext.Current.Request.PhysicalApplicationPath))
    _dataPath += "\" + path
    Return _dataPath
End Function
'Helps to get physical application path of output file
Private Shared Function GetCommonFolder(dtInfo As DirectoryInfo) As String
    Dim _folderNames = dtInfo.GetDirectories("Data")
    If _folderNames.Length > 0 Then
        Return _folderNames(0).FullName
    End If
    Return If(dtInfo.Parent IsNot Nothing, GetCommonFolder(dtInfo.Parent), String.Empty)
End Function