Generic CSV formatting extension that works on `IEnumerable<T>` and returns `IEnumerable<string>`

CsvExtensions.cs

    public static class CsvExtensions
    {
        //
        // sample usage:
        //
        // var list = new object[] {
        //     new { Email = "svetlahristova0@gmail.bg", Name = "Свет.а Х,истова", UnsubscribeToken = "12\r34" },
        //     new { Email = "test", Name = "11\"22", UnsubscribeToken = "5\n67" },
        // };
        // var csv = string.Join(Environment.NewLine, list.ToCsvTable());
        //
        public static IEnumerable<string> ToCsvTable<T>(this IEnumerable<T> list, bool includeHeader = true)
        {
            const string separator = ",";
            const string quote = "\"";
            const int cellLength = 32768;

            var props = typeof(T) != typeof(object) ? typeof(T).GetProperties() : null;
            if (includeHeader)
            {
                var sb = new StringBuilder();
                bool second = false;
                foreach (var prop in props ?? list.First().GetType().GetProperties())
                {
                    sb.Append(second ? separator : null).Append(prop.Name);
                    second = true;
                }
                yield return sb.ToString();
            }
            var escapeChars = new char[] { separator[0], quote[0], Environment.NewLine[0], Environment.NewLine.Last() };
            foreach (var obj in list)
            {
                var sb = new StringBuilder();
                bool second = false;
                foreach (var prop in props ?? obj.GetType().GetProperties())
                {
                    sb.Append(second ? separator : null);
                    second = true;
                    var value = prop.GetValue(obj, null);
                    if (value != null)
                    {
                        if (value is DateTime)
                        {
                            var output = ((DateTime)value);
                            sb.Append(output.ToString("yyyy-MM-dd" + (output.TimeOfDay.TotalSeconds != 0 ? " HH:mm:ss" : null)));
                        }
                        else
                        {
                            var output = value.ToString();
                            // quote string on either containing escape characters or length overflow only
                            if (output.IndexOfAny(escapeChars) < 0 && output.Length < cellLength)
                            {
                                sb.Append(output);
                            }
                            else
                            {
                                output = output.Replace(quote, quote + quote);
                                sb.Append(quote + (output.Length > cellLength - 3 ? output.Substring(1, cellLength - 3) : output) + quote);
                            }
                        }
                    }
                }
                yield return sb.ToString();
            }
        }
    }