title: HttpClient.GetAsync return HttpResponseMessage with null header
body: <p>net 5.0 lover.</p>
  <p>I am new in blazor and .net 5.0, I develop the application with blazor WebAssembly and WebApi.</p>
  <p>There are two major Projects: Client, Server.</p>
  <p>Client is Blazor WebAssembly and Server is WebApi Controller Project.</p>
  <p>In server side, in controller, HttpGet Method, i add a value to Response header:</p>
  <pre><code>        [HttpGet]
      public async Task&lt;ActionResult&lt;IList&lt;Country&gt;&gt;&gt; GetAsync([FromQuery] Pagination paginationDto)
      {
          /...
          httpContext.Response.Headers.Add(&quot;TotalPages&quot;, totalPages.ToString());
          //...
          IList&lt;Country&gt; = ...
          return result;
      }
  </code></pre>
  <p>In Client project razor page, call the api with following method from generic calss:</p>
  <pre><code>        protected virtual async Task&lt;PaginatedResponse&lt;O&gt;&gt; GetAsync&lt;O&gt;(Pagination pagination)
      {
          HttpResponseMessage response = null;
  
          try
          {
              response = await httpClient.GetAsync(RequestUri);
  
              if (response.IsSuccessStatusCode)
              {
                  try
                  {
                      //This response Header always is null!
                      System.Console.WriteLine(&quot;response.Headers: &quot; + response.Headers.ToString());
  
                      O result = await response.Content.ReadFromJsonAsync&lt;O&gt;();
  
                      var paginatedResponse = new PaginatedResponse&lt;O&gt;
                      {
                          Response = result,
                          TotalPages = totalPages
                      };
  
                      return paginatedResponse;
                  }
      //...
          return default;
      }
  </code></pre>
  <p>When Api call from postman the result and Header is fine and TotalPages is there.
  In Client App, the result is ok, but the Header is null.</p>
  <p>Any information will save me ;-)</p>
  <p>Thanks in Advance.</p>