using System;

using System.Collections.Generic;

using System.IO;

using System.Dynamic;

using System.Globalization;

using CsvHelper;

​

public class Program

{

    public static void Main()

    {

        var records = new List<dynamic>();

        dynamic record = new ExpandoObject();

        record.Timestamp = DateTime.UtcNow;

        records.Add(record);

        using (var writer = new StringWriter())

        using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))

        {

            csv.WriteRecords(records);

            writer.ToString().Dump(); // I want the DateTime to be in ISO 8601 format (2020-05-01T15:29:19Z)

        }

    }

}