So now it would nice
to not just show a notification to the user
but to actually do something in our code
when such a notification is received
or when the user taps on it,
because often that is what you wanna do.
If a chat application sends a notification
and the user taps on it, typically you wanna take the user
to that chat the notification belongs to.
And, therefore, here in our dummy app
we can also do something when a notification is received.