addAdId method
Registers adId to watch for ad-ready events.
callback is invoked on the Dart side when the native SDK signals that
the ad slot is ready. Calling this with an already-registered adId
updates the callback.
Implementation
void addAdId(String adId, AdCallback callback) {
_callbacks[adId] = callback;
if (!_adIds.contains(adId)) {
_adIds.add(adId);
} else {
Logger.w("$adId already added, update callback");
}
}