Forcing download of a type in Asp Mvc C#

Force_Download

var bytes = Encoding.UTF8.GetBytes(sb.ToString());

Stream stream = new MemoryStream(bytes);
stream.Flush();
stream.Position = 0;

Response.ContentType = "text/plain";
Response.AppendHeader("content-disposition", "attachment;filename=exportacao");

return new FileStreamResult(stream, "text/plain");