@SafeVarargs
    public final ServerListenerBuilder whenStopped(Consumer<? super Server>... consumers) {
        return whenStopped(Arrays.asList(consumers));
    }
Add {@link Consumer}s invoked when the {@link Server} is stopped.

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