lifecycleInit method
Implementation
Future<void> lifecycleInit() async {
_token = await _channel.invokeMethod("OneSignal#pushSubscriptionToken");
_id = await _channel.invokeMethod("OneSignal#pushSubscriptionId");
_optedIn = await _channel.invokeMethod("OneSignal#pushSubscriptionOptedIn");
return await _channel.invokeMethod("OneSignal#lifecycleInit");
}