code: @SuppressWarnings("checkstyle:hiddenfield")
    private <T extends Time> void subscribe(final Class<T> eventClass, final Set<EventHandler<T>> handlers) {
      for (final EventHandler<T> handler : handlers) {
        LOG.log(Level.FINEST, "Subscribe: event {0} handler {1}", new Object[] {eventClass.getName(), handler});
        this.handlers.subscribe(eventClass, handler);
      }
    }
docs: Register event handlers for the given event class.
  @param eventClass Event type to handle. Must be derived from Time.
  @param handlers One or many event handlers that can process given event type.
  @param <T> Event type - must be derived from class Time. (i.e. contain a timestamp).