How to add action button when message type is notification of Firebase Messaging in Android?

[jja08111]

Situation

On iOS, data-only messages are not reliable when the app is killed. So, I have to use mixed or notification messages. My application has notifications that should contain action buttons. It's easy to add action buttons to data-only messages, but it's not as straightforward with notification messages. On iOS, action buttons can be added using a notification extension. I wonder how to add action buttons in Android as well. Thanks.