code: public final void removeChildRouter(@NonNull Router childRouter) {
          if ((childRouter instanceof ControllerHostedRouter) && childRouters.remove(childRouter)) {
              childRouter.destroy(true);
          }
      }
docs: Removes a child {@link Router} from this Controller. When removed, all Controllers currently managed by
  the {@link Router} will be destroyed.
  
  @param childRouter The router to be removed