awsiot-9.js

// C# .Net
client.UseApplicationMessageReceivedHandler(e =>
{
  Console.WriteLine("### RECEIVED APPLICATION MESSAGE ###");
  Console.WriteLine($"+ Topic = {e.ApplicationMessage.Topic}");
  Console.WriteLine($"+ Payload = {Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}");
  Console.WriteLine($"+ QoS = {e.ApplicationMessage.QualityOfServiceLevel}");
  Console.WriteLine($"+ Retain = {e.ApplicationMessage.Retain}");
  Console.WriteLine();
  Task.Run(() => client.PublishAsync("hello/world"));
});