Program.cs

        private static void GetMixedContent(string[] urls)
        {
            // generate log file and header
            WriteHeader();

            // chrome option
            var options = new ChromeOptions();
            options.AddArgument("--headless");
            options.AddArgument("--no-sandbox");

            // set parallelism
            // 1. not define -> set default value (10)
            // 2. invalid value -> sequential
            // 3. below 1 -> sequential
            // 4. others -> parallel
            var useParallel = Environment.GetEnvironmentVariable("COUNT") ?? "10";
            var isSequential = !int.TryParse(useParallel, out var parallelism) || parallelism <= 1;

            // run
            if (isSequential)
            {
                using (var chrome = new ChromeDriver(Path.GetDirectoryName(Assembly.GetEntryAssembly().Location), options))
                {
                    foreach (var url in urls)
                    {
                        RunDriver(chrome, url);
                    }
                }
            }
            else
            {
                Parallel.ForEach(urls, new ParallelOptions { MaxDegreeOfParallelism = parallelism }, (url, state, i) =>
                {
                    using (var chrome = new ChromeDriver(Path.GetDirectoryName(Assembly.GetEntryAssembly().Location), options))
                    {
                        RunDriver(chrome, url);
                    }
                });
            }
        }

        private static void RunDriver(ChromeDriver chrome, string url)
        {
            Console.WriteLine($"checking {url}");
            var manager = chrome.Manage();
            manager.Timeouts().ImplicitWait = TimeSpan.FromMinutes(2);

            chrome.Url = url;
            var logs = manager.Logs.GetLog("browser");
            var mixedContentLogs = logs.Where(x => Regex.IsMatch(x.Message, ".*Mixed Content:.*")).ToArray();
            if (mixedContentLogs.Any())
            {
                Console.ForegroundColor = ConsoleColor.Yellow;
                foreach (var log in mixedContentLogs)
                {
                    Console.WriteLine($"  > {mixedContentLogs.Length} MixedContent found.");
                    Console.WriteLine($"  * {log.Timestamp} ({log.Level}): {log.Message}");
                    WriteContent(url, log.Timestamp.ToString("s"), log.Level.ToString(), log.Message);
                }
                Console.ForegroundColor = orgColor;
            }
        }