android - FirebaseMessaging.getInstance(firebaseApp) for secondary app supposed to be public but it's private?

Question

I'm trying to subscribe to an FCM (Firebase Cloud Messaging) topic for a secondary Firebase App and according to the documentation this could be done by the overloaded getInstance which takes the secondary FirebaseApp instance as a parameter:

https://firebase.google.com/docs/reference/admin/java/reference/com/google/firebase/messaging/FirebaseMessaging#public-static-synchronized-firebasemessaging-getinstance-firebaseapp-app

public static synchronized FirebaseMessaging getInstance (FirebaseApp app)

Gets the FirebaseMessaging instance for the specified FirebaseApp.

I'm using Kotlin and I'm pulling in the package in build.gradle like this:

implementation "com.google.firebase:firebase-messaging:20.2.0"

But when I try to instantiate the FirebaseMessaging with the overloaded getInstance, I get an error stating that it's not accessible. When I look at the package source, the decompilation shows that the overloaded constructor is not public like the parameterless getInstance:

public class FirebaseMessaging {
    public static final String INSTANCE_ID_SCOPE = "FCM";
    private final Context zzb;
    private final FirebaseInstanceId zzc;
    private final Task<zzab> zzd;
    @Nullable
    @SuppressLint({"FirebaseUnknownNullness"})
    @VisibleForTesting
    static TransportFactory zza;

    @NonNull
    public static synchronized FirebaseMessaging getInstance() {
        return getInstance(FirebaseApp.getInstance());
    }

    @Keep
    @NonNull
    static synchronized FirebaseMessaging getInstance(@NonNull FirebaseApp var0) {
        return (FirebaseMessaging)var0.get(FirebaseMessaging.class);
    }

Did I miss something?

Answer 1

Waitting for answers