//Callback for MQTT unsubscription.
async void IServiceCallback.MQTTUnsubscribe(String topic)
{
await mqttClientSemaphore.WaitAsync();
try
{
ServiceLogic.ManagedMqttUnsubscribe(managedMqtt, topic);
m_topicSet.Remove(topic);
}
finally
{
mqttClientSemaphore.Release();
}
}