some changes

src/main.ts

@@ -1,14 +1,18 @@
 import * as log from './log'
-import * as MqttClient from './mqttclient'
+import * as mqtt from './mqttclient'
 
 class Dispatcher {
-    private _mqttClient: MqttClient.MqttClient
+    private _mqttClient: mqtt.MqttClient
 
     constructor() {
-        this._mqttClient = new MqttClient.MqttClient()
+        this._mqttClient = new mqtt.MqttClient()
 
-        this._mqttClient.register('IoT/test', null)
-        this._mqttClient.register('IoT/Device/#', null)
+        this._mqttClient.register('IoT/test', (message: any) : any => {
+            log.info("Callback for IoT/test")
+            log.info(`message is ${message}`)
+            return `<<${message}>>`
+        })
+        this._mqttClient.register('IoT/Device/#', mqtt.passThrough)
     }
 
     exec() : void {