Executing code after app.Run in .NET Core

A short note on running code around app.Run() in .NET Core while respecting the application lifecycle.

First, let us define a middleware class.

public class StartUp
{
     private readonly RequestDelegate next;
     private bool running = false;

     public StartUp(RequestDelegate next)
     {
         this.next = next;
     }

     public Task Invoke(HttpContext httpContext)
     {
         if (!running)
         {
             //The code we want to run
             running = true;
         }
         return next(httpContext);
     }
}

Now let us add this class to our Program.cs file.
The part we add should preferably be right before the app.Run() statement.

app.UseMiddleware(app);
app.Run();
After this operation, our middleware class will be registered in our project and, due to the life cycle of the .NET Core platform, it will be invoked on every request.
The reason we add it last is to avoid trouble accessing definitions that may be created in earlier operations. (There is no special meaning :))