processPushMessage method
Decrypt an FCM/APNs push payload for an existing conversation (looked up by topic).
Returns a list of decoded messages — usually 1, occasionally more if the
envelope contained multiple. Each entry mirrors getMessagesAfterDate shape.
Implementation
Future<List<Map<String, dynamic>>> processPushMessage(String topic, Uint8List encryptedBytes) {
throw UnimplementedError('processPushMessage() has not been implemented.');
}