Font Size not being set

I am trying to write text to a new page that i create,
I copied the PDFTron examples to set font type and size but it doesn't set it.
here is my code snippet:

     var page = _doc.PageCreate(new Rect(0,0,612, 794));
     ElementWriter writer = new ElementWriter();
     ElementBuilder eb = new ElementBuilder();
     eb.Reset(); // Reset GState to default

     var element = eb.CreateTextBegin(Font.Create(_doc, Font.StandardType1Font.e_times_roman), 12);
     if (!string.IsNullOrWhiteSpace(_from))
       element = eb.CreateTextRun(string.Format("From: {0}", _from));
       element.SetTextMatrix(10, 0, 0, 10, 0, 600);
       element.GetGState().SetLeading(15); // Set the spacing between lines
       var data = element.GetTextDataSize();
     writer.End(); // save changes to the current page
     return page;

You may want to start from ElementBuilder sample project where the code snippet drawing clearly works:

then tweak it see where you went wrong. For example, One possibility is that the text size is just too big (text matrix scale factor is 10x and font size is 12pt, so the actual size on page is 120pt). Is _from empty? Also what do you mean with font size not being set? You see text bug changing the font size has no effect?