*
 * <p>Here is a simple example of how to use a {@code ServiceManager} to start a server.
 *
 * {@snippet :
 * class Server {
 *   public static void main(String[] args) {
 *     Set<Service> services = ...;
 *     ServiceManager manager = new ServiceManager(services);
 *     manager.addListener(new Listener() {
 *         public void stopped() {}

      return;
    }
    Service a = new NoOpDelayedService(150);
    Service b = new NoOpDelayedService(353);
    ServiceManager serviceManager = new ServiceManager(asList(a, b));
    serviceManager.startAsync().awaitHealthy();
    ImmutableMap<Service, Long> startupTimes = serviceManager.startupTimes();
    assertThat(startupTimes).hasSize(2);
    assertThat(startupTimes.get(a)).isAtLeast(150);