@Override
    public ServerBuilder decorator(
            String pathPattern, DecoratingHttpServiceFunction decoratingHttpServiceFunction) {
        virtualHostTemplate.decorator(pathPattern, decoratingHttpServiceFunction);
        return this;
    }
Decorates {@link HttpService}s whose {@link Route} matches the specified {@code pathPattern}.
The specified decorator(s) is/are executed in reverse order of the insertion.

@param decoratingHttpServiceFunction the {@link DecoratingHttpServiceFunction} that decorates
                                     {@link HttpService}.
core/src/main/java/com/linecorp/armeria/server/ServerBuilder.java