code: public static void register(Binder binder, Annotation annotation)
    {
      registerKey(binder, Key.get(new TypeLiteral<DruidNode>(){}, annotation));
    }
docs: Requests that the annotated DruidNode instance be injected and published as part of the lifecycle.
  
  That is, this module will announce the DruidNode instance returned by
  injector.getInstance(Key.get(DruidNode.class, annotation)) automatically.
  Announcement will happen in the ANNOUNCEMENTS stage of the Lifecycle
  
  @param annotation The annotation instance to use in finding the DruidNode instance, usually a Named annotation