Safely signing out using FirebaseAuth in Android

Signout.java

//Declaration and defination
private FirebaseAuth firebaseAuth;
FirebaseAuth.AuthStateListener authStateListener = new FirebaseAuth.AuthStateListener() {
    @Override
    public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
        if (firebaseAuth.getCurrentUser() == null){
            //Do anything here which needs to be done after signout is complete
            signOutComplete();
        }
        else {
        }
    }
};

//Init and attach
firebaseAuth = FirebaseAuth.getInstance();
firebaseAuth.addAuthStateListener(authStateListener);

//Call signOut()
firebaseAuth.signOut();