title: RestSharp Accept header change
body: <p>I am using RestSharp for developing on the client side. I am also using Ruby Grape gem for my custom API on server side. Grape gem can do versioning by setting Accept HTTP header f.e to <code>application/vnd.twitter-v1+json</code></p>
  
  <p>And test command via console works perfect</p>
  
  <pre><code>curl -H Accept=application/vnd.twitter-v1+json /statuses/public_timeline
  </code></pre>
  
  <p>But when I am trying to set up header for RestRequest I am getting <code>error 404</code> on the server.</p>
  
  <p>I have no idea why so. I have found another issue that server returns <code>406 error</code> - but in my case 404.</p>
  
  <p>How can I put custom value for Accept header?</p>