title: API File Upload using HTTP content not exposed in swagger
body: <p>I am implementing a swagger interface into an existing web API. The current API controller exposes an async upload function which uses the <code>Request.Content</code> to transport an image asynchronously. The code that has been used is explained in <a href="http://www.c-sharpcorner.com/article/upload-and-save-multipartform-data-in-webapi-2/" rel="noreferrer">this</a> article.</p>
  
  <p>My api controller:</p>
  
  <pre><code>    [HttpPost]
      [Route("foo/bar/upload")]
      public async Task&lt;HttpResponseMessage&gt; Upload()
      {
          if (!Request.Content.IsMimeMultipartContent())
          {
              throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
          }
          var provider = await Request.Content.ReadAsMultipartAsync(new InMemoryMultipartFormDataStreamProvider());
          NameValueCollection formData = provider.FormData;
          HttpResponseMessage response;
          //access files  
          IList&lt;HttpContent&gt; files = provider.Files;
          if (files.Count &gt; 0)
          {
              HttpContent file1 = files[0];
              using (Stream input = await file1.ReadAsStreamAsync())
              {
                  object responseObj = ExternalProcessInputStream(input)
                  response = Request.CreateResponse(HttpStatusCode.OK, responseObj);
              }
          }
          else 
          {
              response = Request.CreateResponse(HttpStatusCode.BadRequest);
          }
          return response;
      }
  </code></pre>
  
  <p>This works dandy, but when i expose this through swagger i have a parameterless function, which returns an error when used. </p>
  
  <p>My question is how can supply a proper value to test this method with?</p>