C# 9 Record Types: Automatic Modified Date

Program.cs

using System;

var foo = new Foo("foo");
var bar = foo with { Name = "bar" };

Console.WriteLine(foo);
Console.WriteLine(bar);
// Foo { CreatedOn = 7/15/2022 21:39:43, UpdatedOn = , Name = foo }
// Foo { CreatedOn = 7/15/2022 21:39:43, UpdatedOn = 7/15/2022 21:39:43, Name = bar }

abstract record Base
{
    protected Base(Base original)
    {
        CreatedOn = original.CreatedOn;
        UpdatedOn = DateTime.Now;
    }

    public DateTime CreatedOn { get; init; } = DateTime.Now;

    public DateTime? UpdatedOn { get; init; }
}

record Foo(string Name) : Base;

https://sharplab.io/#gist:cbfc1414b555df89030fb217dd277697