Etag is not present in response header

See more:

C#

ASP

MVC

I'm traying to set Etag in response header, but when i check response header in browser i can't see it. By the way this only applies to Etag, i can see another tag and value. By the way i can see it on localhost but when i publish that code to server i cant see.

https://i.stack.imgur.com/j9Aho.png[^]

public static void InsertETag(HttpResponseBase response, Model model)
  {
  

   try
   {
  
    var eTagValue = CalculateETag(model);
    if (!string.IsNullOrEmpty(eTagValue))
    {
   
     
     var matchETagValue = HttpContext.Current.Request.Headers["If-None-Match"];
     if (matchETagValue != null && matchETagValue == eTagValue)
     {
      response.SuppressContent = true;
      response.StatusCode = 304;
      response.StatusDescription = "Not Modified";
      response.Headers["Content-Length"] = "0";
      response.AppendHeader("ETag", eTagValue);
     }
     else
     {
      response.AppendHeader("ETag", eTagValue);
     }
    }
   }
  }

What I have tried:

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