Static middleware template

Middleware.cs

using AppFunc = Func<IDictionary<string, object>, Task>;
using MidFunc = Func<
        Func<IDictionary<string, object>, Task>,
        Func<IDictionary<string, object>, Task>
      >;
      
public static class MyMiddleware
{
    public static MidFunc UseMyMiddleware()
    {
        return
          next =>
          env => 
            {
              //before
              await next(env);
              //after
            }
    }
}