Task throttling using TAP and .NET v4.5

TaskThrottle.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace ProducerConsumerTest
{
  class Program
  {
    private const int MAX_CONCURRENCY_LEVEL = 5;
    private const int NUM_PAGES = 20;

    private static List<Task<int>> _taskList;

    static void Main(string[] args)
    {
      var task = MainInternal();
      task.Wait();
      Console.WriteLine("All tasks completed");

      Console.ReadKey();
    }

    private static async Task MainInternal()
    {
      _taskList = new List<Task<int>>();
      var p = 1;
      while (p <= NUM_PAGES && p < MAX_CONCURRENCY_LEVEL)
      {
        _taskList.Add(SampleTaskAsync(p));
        p++;
      }

      while (_taskList.Count > 0)
      {
        var finishedTask = await Task.WhenAny(_taskList);
        _taskList.Remove(finishedTask);
        if (p > NUM_PAGES)
        {
          continue;
        }
        _taskList.Add(SampleTaskAsync(p));
        p++;
      }
    }

    private static async Task<int> SampleTaskAsync(int pageNo)
    {
      var rnd = new Random((int)DateTime.Now.Ticks);
      var delay = rnd.Next(2000) + 500; 
      Console.WriteLine("Sending page {0}, delay is {1} ms", pageNo, delay);

      await Task.Delay(delay);

      return pageNo;
    }
  }
}