using System.Collections.Generic;

using System.Net.Http;

using System.Threading.Tasks;

namespace HttpLoop

{

    public static class Program

    {

        public static async Task Main(string[] args)

        {

            var products = new List<string>();

            for (var productId = 0; productId < 1000000; ++productId)

            {

                var product = await GetProduct(productId);

                products.Add(product);

            }

            // handle products...

        }

        private static async Task<string> GetProduct(int productId)

        {

            var response = await new HttpClient().PostAsync($"https://www.example.ru/{productId}/product", default);

            return await response.Content.ReadAsStringAsync();

        }

    }

}