title: ASP.NET Core, route is not triggered when defined as OpenId SignedOutCallbackPath
body: <p>I have this controller</p>
  
  <pre><code>    [Route("Authentication")]
      public class AuthenticationController : Controller
      {
  </code></pre>
  
  <p>and this action</p>
  
  <pre><code>        [HttpGet("SignOut")]
          public async Task&lt;IActionResult&gt; SignOut([FromQuery] string sid)
          {
              await ControllerContext.HttpContext.SignOutAsync(Microsoft.AspNetCore.Authentication.OpenIdConnect.OpenIdConnectDefaults.AuthenticationScheme);
              await ControllerContext.HttpContext.SignOutAsync(Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationDefaults.AuthenticationScheme);
  
  
              return View();
  </code></pre>
  
  <p>This works as expected.</p>
  
  <p>But when I configure a SignedOutCallbackPath for my OpenId authentication that has the same route, it doesn't work anymore. The constructor of my controller is not called, the action is not hit and the result in the browser is a blank page (code 200) with html/head/body, but all empty, that doesn't match any template or view.</p>
  
  <pre><code>            services.AddAuthentication(options =&gt;
              {
                  options.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                  options.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
              })
              .AddCookie(options =&gt;
              {
                  options.Cookie.HttpOnly = true;
              })
              .AddOpenIdConnect(options =&gt;
              {
                  options.SignedOutCallbackPath = "/Authentication/SignOut";
  </code></pre>
  
  <p>Is the SignedOutCallbackPath not supposed to be a view of my own?</p>