serving a large PDF file using Response.BinaryWrite

        var bytes = convertToBytes(dir + fileName);        Response.ContentType = "Application/pdf";           Response.BinaryWrite(bytes);        Response.End(); My code excutes it in a new browser window (open.window()).
Instead of having the user wait, I would like to "stream" the file in chunks, so the browser displays the first couple of pages while the rest of the PDF is being trasmitted. 
If that is not feasible, at least I would like to display a message on the new browser window that a file is being retrieve.  Right now, it display a blank page with the dial spinning in the tab, which isn't too visilbe to the user.