Add a listenToAll function the NullConnector. (#368)

Fixes #366

Co-authored-by: Marcus <laravelecho@luniki.de>

Author: luniki

src/channel/null-channel.ts

@@ -25,6 +25,13 @@ export class NullChannel extends Channel {
         return this;
     }
 
+    /**
+     * Listen for all events on the channel instance.
+     */
+    listenToAll(callback: Function): NullChannel {
+        return this;
+    }
+
     /**
      * Stop listening for an event on the channel instance.
      */