using System.IO;

using System;

​

public class Program {

    public static void Main() {

        var texto = "meu texto aqui";

        var stream = new MemoryStream();

        StreamWriter writer = new StreamWriter(stream);

        writer.Write(texto);

        writer.Flush();

        stream.Position = 0;

        var reader = new StreamReader(stream);

        var novotexto = reader.ReadToEnd();

        Console.WriteLine(novotexto);

    }

}