Message's listen not working on new created subscription in flutter web environment

Pubnub Dart SDK version: ^4.0.0-beta.0 Dart SDK version: 2.14.3 Fltuter version: Flutter 2.5.2

Works fine in mobile applications. Mobile application output:

I/flutter (26388): Message no. 1
I/flutter (26388): Message no. 2
I/flutter (26388): Message no. 3
I/flutter (26388): Message no. 4
I/flutter (26388): Message no. 5
I/flutter (26388): Message no. 10
I/flutter (26388): Message no. 11
I/flutter (26388): Message no. 12
I/flutter (26388): Message no. 13
I/flutter (26388): Message no. 14
I/flutter (26388): Message no. 15

The issue occurs at flutter web. Flutter web console output :

I/flutter (26388): Message no. 1
I/flutter (26388): Message no. 2
I/flutter (26388): Message no. 3
I/flutter (26388): Message no. 4
I/flutter (26388): Message no. 5

Code:

Future<void> testPubNub() async {
    var pubnub = PubNub(
        defaultKeyset: Keyset(
            subscribeKey: 'subKey',
            publishKey: 'pubKey',
            uuid: UUID('uniqueId')));

    // Subscribe to a channel
    var channel = "getting_started";

    var subscription = pubnub.subscribe(channels: {channel});
    subscription.messages.listen((message) {
      print(message.content);
    });

    // Send a message every second for 5 seconds
    for (var i = 1; i <= 5; i++) {
      await pubnub.publish(channel, 'Message no. $i');
      await Future.delayed(const Duration(seconds: 1));
    }

    // Unsubscribe and quit
    await subscription.cancel();

    var channel2 = "getting_started2";

    var subscription2 = pubnub.subscribe(channels: {channel2});
    subscription2.messages.listen((message) {
      print(message.content);
    });

    // Send a message every second for 5 seconds
    for (var i = 10; i <= 15; i++) {
      await pubnub.publish(channel2, 'Message no. $i');
      await Future.delayed(const Duration(seconds: 1));
    }

    // Unsubscribe and quit
    await subscription2.cancel();
  }

Update: The above issue is happening in local debugging. After building the webpack and using http-server to serve it at local, it's working fine.

pubnub / dart

Message's listen not working on new created subscription in flutter web environment #70