public ServerListenerBuilder whenStarted(Iterable<? extends Consumer<? super Server>> consumers) {
        requireNonNull(consumers, "consumers");
        for (Consumer<? super Server> consumer : consumers) {
            serverStartedCallbacks.add(requireNonNull(consumer, "consumer"));
        }
        return this;
    }
Adds {@link Consumer}s invoked when the {@link Server} is started.

@see ServerListener#serverStarted(Server)
core/src/main/java/com/linecorp/armeria/server/ServerListenerBuilder.java