connect method
Implementation
Future<Either<ScreenMeetError, bool>> connect(String roomId, String userName) async {
final Map result = await channel.invokeMethod(pm.kConnectCommand, {pm.kConnectRoomId: roomId, pm.kConnectUserName: userName});
if (pm.isSuccess(result)) { return Right(true);}
return Left(pm.error(result));
}