Postfix using OAuth2 authentication for relay host

I tried to set up **postfix** with Google as its relay host but failed miserably. Google switched to **OAuth2** authentication and deprecated other authentication methods. This is why I tried to use the new OAuth2 authentication and not the old user/password one. As far as I understand, postfix does not do any SASL authentication itself but relies on other applications like **Cyrus SASL**. And there exists a plugin for Cyrus doing OAuth2 authentication: But from here on I'm lost. I do not understand how to configure postfix/cyrus correctly to use OAuth2 authentication. I managed to set up getmail to fetch mail from Google using OAuth2 authentication. And I was hoping that it would be not much more difficult to do the same with postfix and Cyrus. But I think I was wrong. It's difficult to ask specific questions. I changed the configuration files so many times that I probably screwed it up completely. But I was wondering if there exists more documentation on how to configure postfix to use a relay host with OAuth2 authentication?