create a sample ios app that use 'Local Push Connectivity'

i need a sample ios demo application,

I need to push sample project that works in wider internet is unavailable. It works only internal network
There is support for this under the name apple 'Local Push Connectivity'.
https://developer.apple.com/documentation/networkextension/local_push_connectivity?language=objc

you can see detail in this video
https://developer.apple.com/videos/play/wwdc2020/10113/

demo application must be written in objective c
The server side will be written in any language that will work on ubuntu ( node pythone etc )

The application will connect to our own server, NOT the Apple APNs, and receive the pushes from our server.
critical point application and server application will work in the environment without internet

Acceptance criteria
- the server code must run in ubuntu or docker container
- ios application will connect to our server with inner network (not internet)
- When push is sended from our server, it will be displayed on ios
- application and server application will work in the environment without internet
- server application must have one API endpoint to trigger to send push to the device