title: Set 'Content-Type' header using RestSharp
body: <p>I'm building a client for an RSS reading service. I'm using the <a href="https://github.com/restsharp/RestSharp" rel="noreferrer">RestSharp</a> library to interact with their API.</p>
  
  <p>The API states: </p>
  
  <blockquote>
    <p>When creating or updating a record you must set <code>application/json;charset=utf-8</code> as the <code>Content-Type</code> header.</p>
  </blockquote>
  
  <p>This is what my code looks like:</p>
  
  <pre><code>RestRequest request = new RestRequest("/v2/starred_entries.json", Method.POST);
  request.AddHeader("Content-Type", "application/json; charset=utf-8");
  request.RequestFormat = DataFormat.Json;
  request.AddParameter("starred_entries", id);
  
  //Pass the request to the RestSharp client
  Messagebox.Show(rest.ExecuteAsPost(request, "POST").Content);
  </code></pre>
  
  <p>However; the service is returning an error</p>
  
  <blockquote>
    <p>Error 415: Please use the 'Content-Type: application/json; charset=utf-8' header</p>
  </blockquote>
  
  <p>Why isn't RestSharp passing the header?</p>