Event channel not workinng in IOS

Question

Event channel not workinng in IOS. onlisten method not getting called. Method channel is working fine in IOS. Only issue is with event channel.

In android event channel and method channel working fine.

Has anyone else dealt with this? Any tips or solutions would be really appreciated! Thanks

IOS code

import Flutter
import UIKit

@main
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
      let controller : FlutterViewController = window?.rootViewController as! FlutterViewController

      let eventChannel = FlutterEventChannel(name:"hello_connection/event_channel", binaryMessenger:controller.binaryMessenger)
      eventChannel.setStreamHandler(Hello())
      
    GeneratedPluginRegistrant.register(with: self)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

import Flutter
import UIKit

class Hello: NSObject, FlutterStreamHandler {
    var eventSink: FlutterEventSink?
    
    func onListen(withArguments arguments: Any?, eventSink: @escaping FlutterEventSink) -> FlutterError? {
        self.eventSink = eventSink
        self.eventSink?("hello")
        return nil
    }
    
    func onCancel(withArguments arguments: Any?) -> FlutterError? {
        eventSink = nil
        return nil
    }
}

Flutter code

class ExampleWorld extends StatelessWidget {
  ExampleWorld({super.key});

  static const eventChannel = EventChannel('hello_connection/event_channel');

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: SafeArea(
        child: SizedBox(
          width: double.maxFinite,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.center,
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              ElevatedButton(
                onPressed: () {
                  eventChannel.receiveBroadcastStream().map(
            (map) => print("event channel"),
          );
                },
                child: Text('start event channel'),
              ),
             
            ],
          ),
        ),
      ),
    );
  }
}

Tried with github and stackoverflow