Disable NSwag caching

Allow "fairer" comparison benchmarks by disabling the ability of NSwag's middleware to cache the generated OpenAPI document.

Author: martincostello

src/TodoApp/OpenApi/NSwag/NSwagOpenApiEndpoints.cs

@@ -90,6 +90,11 @@ public static T UseNSwagOpenApi<T>(this T builder)
                     }
                 };
             };
+
+            // For the purposes of comparison with the other implementations in the benchmarks,
+            // disable document caching. Otherwise, NSwag will only generate the OpenAPI document
+            // once and every request for the OpenAPI document becomes essentially "free".
+            settings.CreateDocumentCacheKey = (_) => Guid.NewGuid().ToString();
         });
 
         return builder;