title: Windows HttpClient response header invalid character
body: <p>I'm using HttpClient postAsync method for posting and retriving json. It's working like a charm. 
  But if server return "Ö" character in response header's any field, it throws below exception. </p>
  
  <pre><code>System.ArgumentException ---&gt; System.ArgumentException: [net_WebHeaderInvalidControlChars]
  Arguments:
  Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&amp;Version=4.7.60408.0&amp;File=System.Net.dll&amp;Key=net_WebHeaderInvalidControlChars
  Parameter name: name
     at System.Net.Browser.ClientHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult)
     at System.Net.Browser.ClientHttpWebRequest.&lt;&gt;c__DisplayClasse.&lt;EndGetResponse&gt;b__d(Object sendState)
     at System.Net.Browser.AsyncHelper.&lt;&gt;c__DisplayClass1.&lt;BeginOnUI&gt;b__0(Object sendState)
     --- End of inner exception stack trace ---
     at System.Net.Browser.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state)
     at System.Net.Browser.ClientHttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
     at System.Net.Http.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
     at System.Net.Http.HttpClientHandler.GetResponseCallback(IAsyncResult ar)
  --- End of stack trace from previous location where exception was thrown ---
    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
  </code></pre>