using System;

using System.Collections.Generic;

​

List<int> l = [1, 2, 3, 4, 5];

​

var e = ((IEnumerable<int>)l).GetEnumerator();

DoSomethingWith(e);

DoSomethingWith(e);

​

void DoSomethingWith(IEnumerator<int> e) {

    Console.WriteLine(e.MoveNext());

    Console.WriteLine(e.Current);

}

​