using System;

using System.Linq;

using System.Collections.Generic;

using System.Collections;

​

namespace union

{

    public class Program

    {

        public static void Main(string[] args)

        {

            var enum1 = new MyEnumerable();

            var enum2 = new MyEnumerable();

​

            enum1.Union(enum2).Select(x => x + 1).ToList();

            Console.WriteLine("All done!");

        }

    }

    class MyEnumerable : IEnumerable<long>

    {

        public IEnumerator<long> GetEnumerator()

        {

            return new MyEnumerator();

        }

​

        IEnumerator IEnumerable.GetEnumerator()

        {

            return GetEnumerator();

        }

    }

​

    class MyEnumerator : IEnumerator<long>

    {

        public long Current

        {

            get

            {

                return 0;

            }

        }

​

        object IEnumerator.Current

        {

            get

            {

                return Current;

            }

        }

​

        public bool MoveNext()

        {

            return false;

        }

​

        public void Reset()

        {

            return;

        }

​

        public void Dispose()

        {

            Console.WriteLine("I got disposed");

        }

    }

}