title: Forge Api PATCH request returns 415 "unsupported media type"
body: <p>I am using the Forge API.
  I need to execute PATCH request.
  When I send it using Postman everything is fine, but when I build request using HttpRequestMessage I get a response - "415 unsupported media type".
  By API documentation Content-Type I set to "application/vnd.api+json".</p>
  
  <p>Body of request in Postman</p>
  
  <p><a href="https://i.stack.imgur.com/p4aCw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/p4aCw.png" alt="enter image description here"></a>
  <a href="https://i.stack.imgur.com/6E7QJ.png" rel="nofollow noreferrer">Headers of request in Postman</a></p>
  
  <p><a href="https://i.stack.imgur.com/5ezjd.png" rel="nofollow noreferrer">request object structure</a></p>
  
  <pre><code>JObject jsonApi = new JObject();
              jsonApi.Add("version", "1.0");
              JObject attributes = new JObject();
              attributes.Add("displayName", file.FileName);
              JObject data = new JObject();
              data.Add("type", "items");
              data.Add("id", file.ExternalFileId);
              data.Add("attributes", attributes);
  
              JObject request = new JObject();
              request.Add("jsonapi", jsonApi);
              request.Add("data", data);
  
              using (var httpClient = new HttpClient())
              {
                  HttpRequestMessage http = new HttpRequestMessage
                  {
                      RequestUri = new Uri(url),
                      Method = new HttpMethod("PATCH"),
                      Headers =
                      {
                          { HttpRequestHeader.Authorization.ToString(), "Bearer " + userLastAccessToken },
                          { HttpRequestHeader.Accept.ToString(), "application/vnd.api+json" }
                      }
                  };  
                  http.Content = new StringContent(request.ToString(), Encoding.UTF8, "application/vnd.api+json");
                  HttpResponseMessage responseMessage = await httpClient.SendAsync(http);
              }
  </code></pre>