title: .NET HttpClient send arbitrary Authorization header
body: <p>Using HttpClient is it possible to construct Authorization headers of arbitrary syntax ?</p>
  
  <p>If I use the syntax HttpClient expects : </p>
  
  <pre><code>HttpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("OAuth2", &lt;token&gt;);
  </code></pre>
  
  <p>it will pass this header : </p>
  
  <pre><code>Authorization: OAuth2 &lt;token-value&gt;
  </code></pre>
  
  <p>However, I'm sending my requests to a remote REST API that requires the authorization header to be in this format :</p>
  
  <pre><code>Authorization: token &lt;token-value&gt;
  </code></pre>
  
  <p>How to send the required format ? </p>