CsvHelper not writing anything to memory stream

Putting all these together (and the comments for corrections), including resetting the memory stream position, the final solution for me was;

        using (MemoryStream ms = new MemoryStream())
        {
            using (TextWriter tw = new StreamWriter(ms))
            using (CsvWriter csv = new CsvWriter(tw))
            {
                csv.WriteRecords(errors); // Converts error records to CSV

                tw.Flush(); // flush the buffered text to stream
                ms.Seek(0, SeekOrigin.Begin); // reset stream position

                Attachment a = new Attachment(ms, "errors.csv"); // Create attachment from the stream
                // I sent an email here with the csv attached.
            }
        }

In case the helps someone else!

Put csvWriter.Flush(); before you return to flush the writer/stream.

EDIT: Per Jack's response. It should be the stream that gets flushed, not the csvWriter. streamWriter.Flush();. Leaving original solution, but adding this correction.

EDIT 2: My preferred answer is: https://stackoverflow.com/a/22997765/1795053 Let the using statements do the heavy lifting for you

You already have a using block which is great. That will flush your writer for you. You can just change your code slightly for it to work.

using (var memoryStream = new MemoryStream())
{
    using (var streamWriter = new StreamWriter(memoryStream))
    using (var csvWriter = new CsvWriter(streamWriter))
    {
        csvWriter.WriteRecords<T>(records);
    } // StreamWriter gets flushed here.

    return memoryStream.ToArray();
}

If you turn AutoFlush on, you need to be careful. This will flush after every write. If your stream is a network stream and over the wire, it will be very slow.