using System;

using System.Text.Json;

​

public class Foo

{

    public Guid id { get; set; }

    public string name { get; set; }

    public string username { get; set; }

}

​

public class Program

{

    public static void Main()

    {

        string json = "{\"id\":\"7a5b1113-ba91-4478-9747-88eb6abce250\",\"name\":\"-Va\\u00d1\\u0096n\",\"username\":\"Vain\"}";

        Foo foo = JsonSerializer.Deserialize<Foo>(json);

        Console.WriteLine(foo.id);

        Console.WriteLine(foo.name);

        Console.WriteLine(foo.username);

        Console.WriteLine(JsonSerializer.Serialize(foo));

    }

}