How to preserve Tamil language in a PDF document

using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;

Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Graphics

//Create a new PDF document
PdfDocument doc = new PdfDocument();
 
//Add a page to the document 
PdfPage page = doc.Pages.Add();
 
//Initialize the PDF page graphics
PdfGraphics graphics = page.Graphics;
 
//Set the font with Unicode option 
Font font = new Font("Nirmala UI", 14);
 
PdfFont pdfFont = new PdfTrueTypeFont(font, true);
 
//Create a new instance for the PdfStringFormrat. 
PdfStringFormat format = new PdfStringFormat();
 
//Set the format as complex script layout type
format.ComplexScript = true;
           
//Draw the text to page graphics
graphics.DrawString("பேசுதல்", pdfFont, PdfBrushes.Black, new RectangleF(0, 0, page.GetClientSize().Width, page.GetClientSize().Height), format);
            
//Save the document
doc.Save("output.pdf");
           
//Close the document
doc.Close(true);

'Create a new PDF document
Dim doc As New PdfDocument()
 
'Add a page to the document
Dim page As PdfPage = doc.Pages.Add()
 
'Initialize the PDF page graphics
Dim graphics As PdfGraphics = page.Graphics
 
'Set the font with Unicode option
Dim font As New Font("Nirmala UI", 14)
 
Dim pdfFont As PdfFont = New PdfTrueTypeFont(font, True)
 
'Create a new instance for the PdfStringFormrat
Dim format As New PdfStringFormat()
 
'Set the format as complex script layout type 
format.ComplexScript = True
 
'Draw the text to page graphics
graphics.DrawString("பேசுதல்", pdfFont, PdfBrushes.Black, New RectangleF(0, 0, page.GetClientSize().Width, page.GetClientSize().Height), format)
 
'Save the document
doc.Save("output.pdf")
 
'Close the document
doc.Close(True)