var list = batch.ToList();

using (var stream = new MemoryStream())

{

    var writer = new BinaryWriter(stream);

    writer.Write(list.Count);

​

    foreach (var item in list)

    {

        writer.Write(item.ToString());

    }

​

    yield return stream.ToArray();

​

    writer.Close();

    writer.Dispose();

}