Hello experts, I have a PWA and I want to add push notifications for android and IOS. For now I am trying to avoid using firebase that I ve seen that could be a solution to this. I am trying to make them work using a javascript nanoflow. To achieve that I see that I need to use a service worker. but I dont see in the service-worker.js file anything that would help me and I am a bit lost can anyone help me with this? how can I use the service worker to make the showNotifications work? and will this work in general when the app is closed? or on IOS which I know is a bit problematic the notification I want to send is just a string nothing complicated and it wont need to change thats why I think using firebase for notifications is a bit of an overkill Thank you in advance for you help