Get size of an zip file from server and progress in Kb?

I want to download a zip file from my server and show progress bar in kb/s or mb/s

i have implemented this code:

     private IEnumerator DOWNLOADZIP(string URL)
     {
     ShowText.SetActive (true);
     showpath.GetComponent<Text>().text = "Downloading...";

         WWW www = new WWW (URL);

     while( www.progress < 1 )
     {
         float m_CurrentValue = www.progress * 100;
         Debug.Log( string.Format( "Progress - {0}%. from {1}", www.progress * 100, www.url ) );
         yield return new WaitForSeconds( .1f );
     }

         yield return www;
         byte[] data = www.bytes;
     File.WriteAllBytes (BookPath + "/Book02.zip" , data);
 
     
     if (File.Exists (zipPath) == false) {
         Debug.LogError (zipPath + " is not found!");
         System.Diagnostics.Process.Start (Path.GetDirectoryName (zipPath));
     
     } else {

         showpath.GetComponent<Text> ().text = "Download Complete.";
         PlayerPrefs.SetString ("Book02_Download4", "true");
         ZipUtil.Unzip (zipPath, BookPath);
         Activity.GetComponent<Button> ().enabled = true;
         SingAlong.GetComponent<Button> ().enabled = true;
     }

May be similar to this thread i want....

Can you help with this @PhiseG1