How exactly can I “create a ‘High Priority’ notification channel on Android” as mentioned in the Firebase documentation?

The following is mentioned in the Firebase documentation here: https://firebase.google.com/docs/cloud-messaging/flutter/receive

Foreground and Notification messages

Notification messages which arrive while the application is in the foreground will not display a visible notification by default, on both Android and iOS. It is, however, possible to override this behavior:

• On Android, you must create a “High Priority” notification channel.
• On iOS, you can update the presentation options for the application.

For iOS, I managed to display messages while the app is in the foreground by writing the following code (after researching, since setForegroundNotificationPresentationOptions isn’t mentioned in the above documentation):

await FirebaseMessaging.instance.setForegroundNotificationPresentationOptions(
  alert: true,
  badge: false,
  sound: true,
);

However, this setForegroundNotificationPresentationOptions did not work for Android. How exactly should I “create a ‘High Priority’ notification channel” as the documentation suggests?

I’ve tried setting the priority in the “Compose Notification”(Firebase Console) settings to High or IMPORTANCE_HIGH, but it didn’t have any effect (notifications appear when the app is in the background, but not in the foreground).

Many resources online suggest using the flutter_local_notifications package for Android. While I am open to using it if necessary, the official Firebase documentation does not mention flutter_local_notifications at all.

If flutter_local_notifications is indeed required, I will use it, but it seems inconsistent with the documentation’s statement that “it is possible to override this behavior” and “On Android, you must create a ‘High Priority’ notification channel.”

Is there a way to override this behavior on Android simply by creating a “High Priority” notification channel as described in the documentation?

References:

• How to specify Android notification channel for FCM push messages in Android 8
• https://developer.android.com/develop/ui/views/notifications/channels
• https://zenn.dev/rafekun/articles/ef8a22f9fe90bd (Japanese)