Strategy interface for customizing
web server factories
beans of this type will get a callback with the server factory before the server itself
is started, so you can set the port, address, error pages etc.
Beware: calls to this interface are usually made from a
WebServerFactoryCustomizerBeanPostProcessor which is a
BeanPostProcessor (so called very early in the ApplicationContext lifecycle).
It might be safer to lookup dependencies lazily in the enclosing BeanFactory rather
than injecting them with