【C#】Max concurrent tasks

static void Main()
{
    Foo();
    Console.ReadLine();
}

private static async Task Foo()
{
    var urls = new[] {
        "A",
        "B",
        "C",
        "D",
        "E",
    };
    var maxThreads = 4;
    var q = new ConcurrentQueue<string>(urls);
    var tasks = new List<Task>();
    for (int n = 0; n < maxThreads; n++)
    {
        tasks.Add(Task.Run(async () =>
        {
            while (q.TryDequeue(out string url))
            {
                Console.WriteLine($"start {url}");
                await Task.Delay(3000);
                Console.WriteLine($"end {url}");
            }
        }));
    }
    await Task.WhenAll(tasks);
}

ref: sound code