MemoryStream as input to file download?

I tried using a memorystream as input to an xml file download, so I wouldn't have to create a disk file (to then delete)....

            Response.Clear()
            Response.AddHeader("Content-Disposition", "attachment; filename=" & varFileName)
            Response.ContentType = "text/XML"
            '    Response.WriteFile(varFilePath & varFileName)  < the alt way to do it

            ''---  use memorystream
            varMemTab.Position = 0
            Dim wrkStreamReader As New StreamReader(varMemTab, Encoding.UTF8)
            Dim content As String = wrkStreamReader.ReadToEnd()
            ''---- do the write
            Response.WriteFile(content)

....but it gave an http exception error like it was processing the markup in the Response.WriteFile(content) statement.

Might there be a way to make this work?

Any suggestions would be appreciated.

Thanks!