i had a problem in reading pdf from external server .

i had changed Server mappath to Resolveurl on string FilePath , it works but it takes too much time too load ,(approximatly 4min to load),why its happning,See below

//string FilePath = Server.MapPath("sa.pdf");

And changed code is:

string FilePath = ResolveUrl("http://www.textbooksonline.tn.nic.in/Books/Std07/Std07-II-TamEng.pdf");
WebClient User = new WebClient();
Byte[] FileBuffer = User.DownloadData(FilePath);
if (FileBuffer != null)
{Response.ContentType = "application/pdf";
Response.AddHeader("content-length", FileBuffer.Length.ToString());
Response.BinaryWrite(FileBuffer);}

Thanks In Advance For Who Helps,