using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        IEnumerable<int> list = new TowelCollection<int>{1, 2, 3, 4};

        Console.WriteLine($"The count is {list.Count()}");

    }

}

​

public class TowelCollection<T> : ICollection<T>

{

    public int Count => -42;

    public void Add(T item) { }

    public void Clear() { }

    public bool Contains(T item) => false;

    public void CopyTo(T[] items, int index) { }

    public bool Remove(T item) => false;

    public bool IsReadOnly => false;

    public IEnumerator<T> GetEnumerator() => null;

    IEnumerator IEnumerable.GetEnumerator() => null;

}