agora - onUserJoined - how to differentiate specific broadcaster/host - agora.io

Question

onUserJoined provides UID which is then used to set up remote video.
in live stream feature when there are two hosts streaming in one channel and if another audience joins later then how can that audience tell which uid is for which host.
Note that onUserJoined does call in random order.
https://docs.agora.io/en/All/API%20Reference/java/classio_1_1agora_1_1rtc_1_1_i_rtc_channel_event_handler.html#a65fd197a39824219aedc2cba81296e82
Use case:
2 hosts already streaming in one channel. 1 of the host is original host and another is a co-host(got invited into the channel)
an audience joins the channel. onUserJoined callback is triggered twice and given the remote UID. That audience now needs to know who is the original host and related his UID and who is the co-host and his related UID.

Answer 1

You basically Answered your self
LIVE_BROADCASTING profile: This callback notifies the app when the host joins the channel. If other hosts are already in the channel, the SDK also reports to the app on the existing hosts. We recommend having at most 17 hosts in a channel.

Answer 2

I finally found a solution for that issue by informing all users that will enter the channel after the Orignal Host by the uid of the orignal host
and you can do this by using sendStreamMessage() function
First joinChannelSuccess triggers after original host login
which will return uid of the original host - and we will save it in a variable.
Then, use sendStreamMessage() to send this uid for all new users
and that by using this function which will be called when userJoined triggers
check this code
int _orignalHost = 'the uid';
_addListener() {
_engine.setEventHandler(RtcEngineEventHandler(
**joinChannelSuccess:** (channel, uid, elapsed) {
setState(() {
isJoined = true;
});
},
**userJoined:** (uid, elapsed) {
remoteUids.add(uid);
setState(() {});
},
// this trriger when you recive the mesage
**streamMessage:** (int uid, int streamId, Uint8List data) {
// save it in _orignalHost variable for the audince
},
streamMessageError:
(int uid, int streamId, ErrorCode error, int missed, int cached) {
},
));
}
Future<void> _onNewUserJoin() async {
try {
var streamId = await _engine
.createDataStreamWithConfig(DataStreamConfig(false, false));
if (streamId != null) {
await _engine.sendStreamMessage(
streamId, Uint8List.fromList(utf8.encode(_orignalHost)));
}
_controller.clear();
} catch (e) {
}
}
you can check full code for StreamMessage:
https://github.com/AgoraIO/Agora-Flutter-SDK/blob/master/example/lib/examples/advanced/stream_message/stream_message.dart
Also, You can check this for more info (anoter solution)
https://docs.agora.io/en/Real-time-Messaging/faq/audience_event?platform=Android