How to detect if peer leaves video call in Flutter using Agora

I have two apps are built in Flutter, Doctor app and Patient app, a Doctor establishes a video call with Patient using Agora RTC Engine (peer-to-peer)..

I'm wondering if there is a way (from front-end) to detect when the other peer has left the call (due the poor connection, being disconnected or even got hang-up.

Here is the library i'm using: agora_rtc_engine

I found the answer if someone is interested.

So first import the library:

import 'package:agora_rtc_engine/rtc_engine.dart';

And then declare this variable:

late RtcEngine _engine;

Then add this function and add your own code:

Future <void> setHandler() async {
    _engine = await RtcEngine.createWithConfig(RtcEngineConfig("$REMOTE_VIDEO_UID"));

    await _engine.enableVideo();

    _engine.setEventHandler(
      RtcEngineEventHandler(
        joinChannelSuccess: (String channel, int uid, int elapsed) {
          print("Local user has joined the call!");
          // Your code goes here
        },

        userJoined: (int uid, int elapsed) {
          print("Local user has joined the call!");
          // Your code goes here
        },

        userOffline: (int uid, UserOfflineReason reason) {
          print("remote user has left the call!");
          // Your code goes here
        },

      ),
    );
  }

And finally call the handler like this within your preferred state:

  setState(
    () {
      setHandler();
    },
  );

Thanks to this guy for his tutorial.