This is only used in one place and therefore will always be HttpRequest.

Emby.Server.Implementations/HttpServer/Security/SessionContext.cs

@@ -45,12 +45,7 @@ namespace Emby.Server.Implementations.HttpServer.Security
 
         public User GetUser(object requestContext)
         {
-            if (requestContext is HttpRequest request)
-            {
-                return GetUser(request.HttpContext);
-            }
-
-            return GetUser((HttpContext)requestContext);
+            return GetUser(((HttpRequest)requestContext).HttpContext);
         }
     }
 }