firebase-admin-go VS go-fcm

I recently tried to fork the firebase-admin-go package and add a few edits that I need for a project. I decided to use a replace directive in my go.mod file but when I do I get this error:

I found this Github Issue on the official firebase SDK asking about event listeners. The developer asking the question wrote an entire addition to integrate event listeners into the SDK and even signed a Google Contributor Licenses but it does not look like this will be integrated. Is there a way that I can take the logic that is already written and put it into my application rather than writing a wrapper around the firebase REST streaming API? It is essentially already written with this pull request.

To use it without the JS SDK, you need to create a server which integrates with their API. This usually means pulling an SDK in on your server which is often okay, though I did find their Go SDK (https://github.com/firebase/firebase-admin-go) rough on the edges. We ultimately abandoned using the service... I think if your integration requires any fine tuning or integration with other services, you might want to look elsewhere.

It seems that gorush uses https://github.com/appleboy/go-fcm for Android's FCM. I can't find any reference to https://github.com/NaySoftware/go-fcm in gorush's repo.