@SafeVarargs
    public final ServerListenerBuilder whenStarted(Consumer<? super Server>... consumers) {
        return whenStarted(Arrays.asList(consumers));
    }
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