using System;

using System.Collections.Generic;

using System.Threading.Tasks;

using System.Diagnostics;

using System.Net.Http;

​

​

public class Program

{

    public static async Task Main()

  {

    Stopwatch stopwatch = new Stopwatch();

    stopwatch.Start();

​

    var pageURLs = new List<string> {

                "https://www.scrapingcourse.com/ecommerce/page/1/",

                "https://www.scrapingcourse.com/ecommerce/page/2/",

                "https://www.scrapingcourse.com/ecommerce/page/3/",

                "https://www.scrapingcourse.com/ecommerce/page/4/",

                "https://www.scrapingcourse.com/ecommerce/page/5/"

            };

​

    // initialize the common HTTP client to make

    // all the requests

    HttpClient client = new HttpClient();

​

    // initialize the list of tasks

    List<Task> tasks = new List<Task>();

​

    // define each task and add it to the list

    foreach (var pageURL in pageURLs)

    {

      tasks.Add(Task.Run(() => ProcessRequest(pageURL, client)));

    }

​

    // wait for all tasks to complete

    await Task.WhenAll(tasks);

​

    // dispose the HTTP client

    client.Dispose();

​

    // get the elapsed time in seconds

    stopwatch.Stop();

    double elapsedTimeS = stopwatch.ElapsedMilliseconds / 1000.0;

    Console.WriteLine($"Elapsed time: {elapsedTimeS}s");

  }

​

  private static void ProcessRequest(string pageURL, HttpClient client)

  {

    var response = client.GetAsync(pageURL).Result;

    Console.WriteLine($"Request to '{pageURL}' completed with status code '{response.StatusCode}'!");

  }

}

​