Send *Statistics and Timestamp messages from SimulatedMessageBridge

This makes the simulation environment much closer to reality.

Change-Id: Ie0f44c17d9c9a750363335def1b008cef8c809b0
diff --git a/aos/events/simulated_event_loop.h b/aos/events/simulated_event_loop.h
index de19b11..bc2721e 100644
--- a/aos/events/simulated_event_loop.h
+++ b/aos/events/simulated_event_loop.h
@@ -105,6 +105,9 @@
   // for things like the logger.
   void DisableForwarding(const Channel *channel);
 
+  // Disables the messages sent by the simulated message gateway.
+  void DisableStatistics();
+
  private:
   const Configuration *const configuration_;
   EventSchedulerScheduler scheduler_scheduler_;