using System;

using System.Collections.Generic;

using System.Collections.Concurrent;

using System.Linq;

​

public static class Program

{

    public static void Main()

    {

        IEnumerable<int> items;

        using (BlockingCollection<int> collection = new())

        {

            items = collection.GetConsumingEnumerable();

        }

​

        Console.WriteLine("Before foreach");

        Console.WriteLine(items.FirstOrDefault()); // Boom

        Console.WriteLine("After foreach");

    }

}

​