joinGroup static method
      
Future<Group?> 
joinGroup(
    
- String guid,
- String groupType, {
- String password = '',
- required dynamic onSuccess(- Group group
 
- required dynamic onError(- CometChatException excep
 
Returns a Group object after joining the logged in user to specified group. In order to start participating in group conversations, you will have to join a group
guid A unique identifier for a group that logged in user wants to join.
groupType needs to be either of the below 3 values public, private, password.
password Mandatory in case group type  is password only.
method could throw PlatformException with error codes specifying the cause
Implementation
static Future<Group?> joinGroup(String guid, String groupType,
    {String password = '',
    required Function(Group group)? onSuccess,
    required Function(CometChatException excep)? onError}) async {
  try {
    final result = await channel.invokeMethod('joinGroup', {
      'guid': guid,
      'groupType': groupType,
      'password': password,
    });
    final res = Group.fromMap(result);
    if (onSuccess != null) onSuccess(res);
    return res;
  } on PlatformException catch (p) {
    _errorCallbackHandler(null, p, null, onError);
  } catch (e) {
    _errorCallbackHandler(null, null, e, onError);
  }
  return null;
}