join method
Joins this channel
If this channel sets accessCode to join, you have to provide
accessCode as parameter. After this method completes successfully,
channel event ChannelEventHandler.onUserJoined will be invoked.
Implementation
Future<void> join({String? accessCode}) async {
await _sdk.api.send(GroupChannelJoinRequest(
channelUrl: channelUrl,
accessCode: accessCode,
));
}