https://www.php.net/manual/it/oauthprovider.tokenhandler.php
PHP: OAuthProvider::tokenHandler - Manual
Set the tokenHandler handler callback
phpmanual
https://helidon.io/docs/v4/apidocs/io.helidon.security.util/io/helidon/security/util/TokenHandler.html
TokenHandler (Helidon Project 4.4.1 API)
declaration: module: io.helidon.security.util, package: io.helidon.security.util, class: TokenHandler
helidonprojectapi