code: func Wrap(handler http.Handler) Handler {
  	return HandlerFunc(func(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
  		handler.ServeHTTP(rw, r)
  		next(rw, r)
  	})
  }
docs: // Wrap converts a http.Handler into a negroni.Handler so it can be used as a Negroni
  // middleware. The next http.HandlerFunc is automatically called after the Handler
  // is executed.