} finally {
        monitor.leave();
      }
      return builder.build();
    }

    ImmutableMap<Service, Long> startupTimes() {
      List<Entry<Service, Long>> loadTimes;
      monitor.enter();
      try {
        loadTimes = Lists.newArrayListWithCapacity(startupTimers.size());
        // N.B. There will only be an entry in the map if the service has started