不会为嵌套集合生成 CSVHelper 标头

问：

尝试将列表转换为CSV文件，我在其中嵌套了集合。

当 CSV 读入对象集合时，转换可以完美工作，但当使用相同的集合使用相同的映射生成 CSV 时，不会生成所有标头。无法弄清楚我做错了什么，生成除名为列的集合之外的所有列，例如.Children, GrandChildren

using CsvHelper;
using CsvHelper.Configuration;
using CsvHelper.TypeConversion;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using Xunit;

namespace CSVHelperNugetHierarchyTest
{
    class Program
    {
        static List<Parent> Parents;
        static List<string> Headers;
        static void Main(string[] args)
        {
            using (var stream = new MemoryStream(Encoding.ASCII.GetBytes(GetCSV())))
            {
                using (var reader = new StreamReader(stream))
                {
                    using (var csv = new CsvReader(reader, new CsvConfiguration(CultureInfo.GetCultureInfo("en-US")) { HasHeaderRecord = true }))
                    {
                        csv.Context.TypeConverterCache.AddConverter<List<Child>>(new ChildrenConverter());
                        csv.Context.TypeConverterCache.AddConverter<List<GrandChild>>(new GrandChildrenConverter());
                        csv.Context.RegisterClassMap<ParentMapper>();
                        csv.Context.RegisterClassMap<ChildMapper>();
                        csv.Context.RegisterClassMap<GrandChildMapper>();
                        Parents = csv.GetRecords<Parent>().ToList();
                        Headers = csv.HeaderRecord.ToList();
                    }
                }
            }

            using (var stream = new MemoryStream())
            {
                using (var writer = new StreamWriter(stream))
                {
                    using (var csv = new CsvWriter(writer, new CsvConfiguration(CultureInfo.GetCultureInfo("en-US")) { HasHeaderRecord = true }))
                    {
                        csv.Context.TypeConverterCache.AddConverter<List<Child>>(new ChildrenConverter());
                        csv.Context.TypeConverterCache.AddConverter<List<GrandChild>>(new GrandChildrenConverter());
                        csv.Context.RegisterClassMap<ParentMapper>();
                        csv.Context.RegisterClassMap<ChildMapper>();
                        csv.Context.RegisterClassMap<GrandChildMapper>();
                        csv.WriteRecords(Parents);
                    }
                }
                var streamBuffer = stream.ToArray();
                var content = Encoding.UTF8.GetString(streamBuffer);
                foreach (var item in Headers)
                {
                    Assert.Contains(item, content);
                }
            }
        }

        static string GetCSV()
        {
            return "Property0,Property1,Property2,Property3,Property4"
                + Environment.NewLine
                + "a,b,c,d,e";
        }
    }
    class Parent
    {
        public string Property0 { get; set; }
        public string Property1 { get; set; }
        public List<Child> Children { get; set; }
    }
    class Child
    {
        public string Property2 { get; set; }
        public string Property3 { get; set; }
        public List<GrandChild> GrandChildren { get; set; }
    }
    class GrandChild
    {
        public string Property4 { get; set; }
    }
    class ParentMapper : ClassMap<Parent>
    {
        public ParentMapper()
        {
            Map(m => m.Property0);
            Map(m => m.Property1);
            Map(m => m.Children).Index(0);
        }
    }
    class ChildMapper : ClassMap<Child>
    {
        public ChildMapper()
        {
            Map(m => m.Property2);
            Map(m => m.Property3);
            Map(m => m.GrandChildren).Index(0);
        }
    }
    class GrandChildMapper : ClassMap<GrandChild>
    {
        public GrandChildMapper()
        {
            Map(m => m.Property4);
        }
    }
    class ChildrenConverter : ITypeConverter
    {
        public object ConvertFromString(string text, IReaderRow row, MemberMapData memberMapData)
        {
            var children = new List<Child>();
            children.Add(row.GetRecord<Child>());
            return children;
        }

        public string ConvertToString(object value, IWriterRow row, MemberMapData memberMapData)
        {
            var children = value as List<Child>;
            foreach (var child in children)
            {
                row.WriteRecord(child);
            }
            return null;
        }
    }
    class GrandChildrenConverter : ITypeConverter
    {
        public object ConvertFromString(string text, IReaderRow row, MemberMapData memberMapData)
        {
            var children = new List<GrandChild>();
            children.Add(row.GetRecord<GrandChild>());
            return children;
        }

        public string ConvertToString(object value, IWriterRow row, MemberMapData memberMapData)
        {
            var children = value as List<GrandChild>;
            foreach (var child in children)
            {
                row.WriteRecord(child);
            }
            return null;
        }
    }
}

收到的输出：

Property0,Children,Property1
a,c,e,d,b

预期输出：

Property0,Property1,Property2,Property3,Property4
a,b,c,d,e

我在 .NET Core 3.1 环境中使用 CsvHelper 版本。27.2.1

尝试了很多方法，例如将列、索引和列 + 索引一起添加。

PS：省略了一些空检查和验证。