How to monitor the network bandwidth usage of a specific application?

using System;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Reflection;
using System.Text;
using System.Threading;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                var bytesSentPerformanceCounter = new PerformanceCounter();
                bytesSentPerformanceCounter.CategoryName = ".NET CLR Networking";
                bytesSentPerformanceCounter.CounterName = "Bytes Sent";
                bytesSentPerformanceCounter.InstanceName = GetInstanceName();
                bytesSentPerformanceCounter.ReadOnly = true;

                var bytesReceivedPerformanceCounter = new PerformanceCounter();
                bytesReceivedPerformanceCounter.CategoryName = ".NET CLR Networking";
                bytesReceivedPerformanceCounter.CounterName = "Bytes Received";
                bytesReceivedPerformanceCounter.InstanceName = GetInstanceName();
                bytesReceivedPerformanceCounter.ReadOnly = true;

                Console.WriteLine("Bytes sent: {0}", bytesSentPerformanceCounter.RawValue);
                Console.WriteLine("Bytes received: {0}", bytesReceivedPerformanceCounter.RawValue);
                Thread.Sleep(1000);
            }
        }

        private static string GetInstanceName()
        {
            string returnvalue = "not found";
          //Checks bandwidth usage for CUPC.exe..Change it with your application Name
            string applicationName = "CUPC"; 
                PerformanceCounterCategory[] Array = PerformanceCounterCategory.GetCategories();
            for (int i = 0; i < Array.Length; i++)
            {
                if (Array[i].CategoryName.Contains(".NET CLR Networking"))
                    foreach (var item in Array[i].GetInstanceNames())
                    {
                        if (item.ToLower().Contains(applicationName.ToString().ToLower()))
                            returnvalue = item;

                    }

            }
            return returnvalue;
        }
    }
}