public ServiceManager startAsync() {
    for (Service service : services) {
      checkState(service.state() == NEW, "Not all services are NEW, cannot start %s", this);
    }
    for (Service service : services) {
      try {
        state.tryStartTiming(service);
        service.startAsync();
      } catch (IllegalStateException e) {
        // This can happen if the service has already been started or stopped (e.g. by another