locale in routes ?

hi

let's say we have $defaultLocale = 'it' and $supportedLocales = ['it','en','fr'];

by using $routes->get('{locale}/', 'Home::index');

the site responds to site/it/ and site/en/ site/fr/

what i would expect is site/ to be defaultLocale and also have site/en/  and site/fr/
site/it/ should trow 404

any suggestion on how can i get this behavior ?

thanks