library; import "package:nt4/nt4.dart"; NT4Client ntClient = NT4Client(serverBaseAddress: '10.5.78.2', onConnect: () { print("NT4 Connected"); }, onDisconnect: () { print("NT4 Disconnected"); }); Map nt4Subscriptions = {}; NT4Subscription subscribe(String topic){ if (!nt4Subscriptions.containsKey(topic)) { NT4Subscription subscrip = ntClient.subscribe(topic, NT4SubscriptionOptions()); nt4Subscriptions[topic] = subscrip; } return nt4Subscriptions[topic]!; } List nt4Topics = [];