/**
   * Waits for the {@link ServiceManager} to become {@linkplain #isHealthy() healthy}. The manager
   * will become healthy after all the component services have reached the {@linkplain State#RUNNING
   * running} state.
   *
   * @throws IllegalStateException if the service manager reaches a state from which it cannot
   *     become {@linkplain #isHealthy() healthy}.
   */
  public void awaitHealthy() {
    state.awaitHealthy();