title: .Net Core 2.1.6 Api Hangs when returning a statuscode 205
body: <p>I have an Api that we need to return a status code 205 from. Whenever this code is hit, the Api just hangs, no response gets returned to PostMan, or to any tests. Even after disabling all middleware and custom libraries, it still behaves in the same way.</p>
  
  <pre><code>   [Route("")]   
     public class PingController : Controller
     {
        // GET
        [HttpGet("ping")]
        public IActionResult Index()
        {
           return StatusCode(205);
        }
    }
  </code></pre>
  
  <p>The below works. 204, 200, 201, etc, all work. 205 causes it to hang.</p>
  
  <pre><code>  [Route("")]   
     public class PingController : Controller
     {
        // GET
        [HttpGet("ping")]
        public IActionResult Index()
        {
           return StatusCode(204);
        }
    }
  </code></pre>
  
  <p>I have no idea what is causing this, and I'm starting to wonder if this is a bug in .Net Core ? Though...it has to be said, a new solution with 2.1 works fine. I have tried to downgrade 2.1.6 to 2.1.1 but it didn't help either.</p>
  
  <p>Just wondering if someone has/had the same problem? It almost feels like a threading thing...</p>
  
  <p>Edit 1.
  Interestingly enough, this works when changing "commandName": "Project" to "commandName": "IISExpress" in launchSettings.json</p>
  
  <p>Edit 2.
  If you return return StatusCode(205, null); then it works fine. This feels like a bug ?</p>