Stream without C#content

Question

Good afternoon guys I have the following code:

 Stream retorno = new MemoryStream();

        using (var stream = new System.IO.StreamWriter(System.IO.File.Open("c:\\Temp\\file2.xml", FileMode.OpenOrCreate, FileAccess.ReadWrite)))
        {
            infoSerializer.Serialize(stream, Functions.ConvertLayoutConsultarSituacaoLoteRpsEnvio(objeto, Functions.PadraoNFSe(codigoMunicipio)));

            StreamReader reader = new StreamReader(retorno);

            Repositorio.XmlConsultarLote = reader.ReadToEnd();

        }

        using (var stream = new System.IO.StreamWriter(retorno))
        {
            infoSerializer.Serialize(stream, Functions.ConvertLayoutConsultarSituacaoLoteRpsEnvio(objeto, Functions.PadraoNFSe(codigoMunicipio)));

            StreamReader reader = new StreamReader(retorno);

            Repositorio.XmlConsultarLote = reader.ReadToEnd();

        }

The first using is how the function was originally, and the second using is what I’m trying to change, well... the goal and not need to create a physical file on the machine, for this I’m trying instead to create the physical file I’m trying to pass the content to a stream, but on arriving at the Repositorio.XmlConsultarLote = reader.ReadToEnd(); Xmlconsultarlote does not receive anything, guess where the error is?