using System;

using System.Text.Json;

using System.Text.Json.Serialization;

​

public class Program

{

    public static void Main()

    {

        var dt=DateTime.Now;

        Console.WriteLine(System.Text.Json.JsonSerializer.Serialize(dt));

        Console.WriteLine(dt.ToString("o"));

        Console.WriteLine(System.Text.Json.JsonSerializer.Deserialize<DateTime>(System.Text.Json.JsonSerializer.Serialize(dt)).ToString("o"));

    }

}