Lazy singleton demo

using System;

namespace ConsoleApp4
{
    class Program
    {
        public class LazyItem
        {
            public readonly string foobar;

            public LazyItem(string foobar)
            {
                this.foobar = foobar;
            }
        }
        public class LazyContainer
        {
            private readonly Lazy<LazyItem> common;
            public LazyContainer()
            {
                common = new Lazy<LazyItem>(() => new LazyItem("common"));
            }
            public LazyItem Common => common.Value;
        }

        // https://msdn.microsoft.com/en-us/library/dd642331(v=vs.110).aspx
        static void Main(string[] args)
        {
            var c1 = new LazyContainer();
            Assert(c1.Common, c1.Common); // ok

            var c2 = new LazyContainer();
            Assert(c1.Common, c2.Common); // not ok
        }

        public static void Assert(object o, object o2)
        {
            if (o.GetHashCode() != o2.GetHashCode())
            {
                throw new Exception();
            }
        }
    }
}