code: func WithContentType(handler http.Handler, contentType string) http.Handler {
  	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  		w.Header().Set("Content-Type", contentType)
  		w.Header().Set("X-Content-Type-Options", "nosniff")
  		handler.ServeHTTP(w, r)
  	})
  }
docs: // WithContentType sets both the Content-Type and the X-Content-Type-Options (nosniff) header