create static method

Implementation

static Future<FlutterBaseInterstitial> create(String zoneId) async {
  MethodChannel commconChannel = FlutterBidmadCommon().platform;
  String channelName = await commconChannel.invokeMethod('initInterstitialChannel');

  FlutterBaseInterstitial instance = FlutterBaseInterstitial._internal(channelName);
  await instance._setAdInfo(zoneId);

  return instance;
}