using System;

public class Program

{

    public static void Main()

    {

        var bar1 = new Bar();

        Console.WriteLine(bar1.Foo);

        var bar2 = new Bar { Foo = Guid.NewGuid() };

        Console.WriteLine(bar2.Foo);

    }

    public class Bar

    {       

        private readonly Guid _guid = Guid.NewGuid(); 

        public Guid Foo { get => _guid; init => _guid = value; }

    }

}