unsubscribeTopic method

void unsubscribeTopic(
  1. String? topic
)

Unsubscribe from a string topic.

Implementation

void unsubscribeTopic(String? topic) {
  if (topic == null) {
    throw ArgumentError(
        'MqttSubscriptionManager::unsubscribeStringTopic - topic is null');
  }
  final subscriptionTopic = MqttSubscriptionTopic(topic);
  final sub = MqttSubscription(subscriptionTopic);
  final msgId = messageIdentifierDispenser.nextMessageIdentifier;
  final unsubscribeMsg = MqttUnsubscribeMessage()
      .withMessageIdentifier(msgId)
      .fromStringTopic(topic);
  _connectionHandler.sendMessage(unsubscribeMsg);
  pendingUnsubscriptions[unsubscribeMsg.variableHeader.messageIdentifier] =
      <MqttSubscription>[sub];
}