protected void shutdown() {
    threadMonitor.close();
    executor.shutdown();
    try {
      executor.awaitTermination(20, TimeUnit.SECONDS);
    } catch (InterruptedException e) {
      throw new InternalGemFireError("Interrupted while waiting for DM shutdown");
    }
  }
Creates a new local distribution manager

@param system The distributed system to which this distribution manager will send messages.
geode-core/src/main/java/org/apache/geode/distributed/internal/LonerDistributionManager.java