code: public void shutdown()
      {
          if (this.isShutdown)
          {
              return;
          }
          this.isShutdown = true;
          for (LogTarget target : this.targets)
          {
              target.shutdown();
          }
          this.factory.remove(this);
      }
docs: Shuts down this Logger and all its LogTargets
  <p>The LogFactory will no longer return this Logger for its id