Topic subscription is self-explanatory. Sometimes within a news app, you won't want to have a notification for all the news. Maybe you want to get the latest and most important news, maybe you want to know today's top games, or you might just want to know your favorite team major news on a daily basis; such an experience is present, available, and doable using the Firebase topic subscription API.
Now, let's see how we can provide such an experience to our users, knowing that the UI can differ from one application to another. Maybe you've got a dashboard for an important news, or sports, or weather, but you might go deeper, providing custom titles or topics.
Firebase topic subscription is smart enough to create a new topic if the topic you want to subscribe to is not registered to a custom topic that Firebase...
