namespace DesignPattern.Creational.Singleton{    public class Singleton    {        private Singleton() { }        private static Singleton _instance;        private static readonly object Obj = new object();        public static Singleton GetInstance()        {            if (_instance == null)            {                lock (Obj)                {                    if (_instance == null)                    {                        _instance = new Singleton();                    }                }            }            return _instance;        }    }    public class NSingleton    {        public static readonly NSingleton Instance = new NSingleton();    }}