How to capture output of Python script in C# as it is printing text while running?

Question

I have following Python script :

import time
for x in range(10):
    print(x)
    time.sleep(0.05)

I want to run this script and capture its output while it is running. I used the following C# code but it does not print any number until it completely finishes loop.

        private void DoScriptTest()
        {
            ProcessStartInfo start = new ProcessStartInfo();
            string cmd = @"c:\flowers\count.py";
            start.FileName = @"C:\Users\pubud\AppData\Local\Programs\Python\Python36\python.exe";
            start.Arguments = string.Format("{0}", cmd);
            start.UseShellExecute = false;// Do not use OS shell
            start.CreateNoWindow = true; // We don't need new window
            start.RedirectStandardOutput = true;// Any output, generated by application will be redirected back
            start.RedirectStandardError = true; // Any error in standard output will be redirected back (for example exceptions)

            Process process = new Process();
            process.StartInfo = start;
            process.EnableRaisingEvents = true;
            process.OutputDataReceived += ProcessOutputHandler;
            process.Start();
            process.BeginErrorReadLine();
            process.BeginOutputReadLine();
            process.WaitForExit();
        }

        private void ProcessOutputHandler(object sender, DataReceivedEventArgs e)
    {
            if (!String.IsNullOrEmpty(e.Data))
                try {
                        TxtPrompt.Invoke((MethodInvoker)delegate {
                            TxtPrompt.AppendText(e.Data);
                            TxtPrompt.Refresh();
                        });
                    }
                    catch
                { }
        }

I am not sure why ProcessOutputHandler is NOT called in while the script is running. How could I get that output ? (the numbers coming from Python script in real time)