using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var data = Seed(5500);

        var lv1 = 0;

        foreach(var list in ToChunks(data, 1000)) {

            lv1++;

            foreach(var i in list) {

                Console.WriteLine(string.Format("{0}: {1}", lv1, i));

            }

        }

    }

    private static IEnumerable<IEnumerable<T>> ToChunks<T>(IEnumerable<T> data, int? size)

    {

        if (size == null)

            yield return data;

        else

        {

            if (size < 1)

                size = 1;

​

            var enuemrator = data.GetEnumerator();

            int current = 0;

            while (enuemrator.MoveNext())

            {

                current++;

                var ret = new List<T>();

                ret.Add(enuemrator.Current);

                while (ret.Count < size.Value && enuemrator.MoveNext())

                    ret.Add(enuemrator.Current);

                yield return ret;

            }

        }

    }

    private static List<int> Seed(int size) {

        var list = new List<int>();

        for(var i = 0; i < size; ++i) {

            list.Add(i);

        }

        return list;

    }

}