How do you properly request notification permission from a user, and what genuinely differs between how Android and iOS each respectively handle this specific particular permission request?

Both platforms genuinely require explicit user permission before an app can actually display push notifications, though they genuinely differ somewhat in exactly how this works, with iOS requiring an explicit runtime permission request through the requestPermission method before any notification can ever actually be displayed at all, while more genuinely recent Android versions similarly now also require this exact same kind of explicit runtime permission request, whereas genuinely older Android versions had previously granted this particular permission completely automatically without ever needing to ask.

NotificationSettings settings = await FirebaseMessaging.instance.requestPermission(
  alert: true,
  badge: true,
  sound: true,
);