Allow listeners and event subscribers to be private

[goetas]

Fixes #593

[weaverryan]

Ha! Was it that easy? :)

Assuming you've tested that this works irl (I'm not very familiar with the JMS event dispatcher), a big +1!

Thanks!

[goetas]

Ha! Was it that easy? :)

actually it turned out to be not that easy. the previous implementation had the side effect that services become not-lazy...

the current solution requires at least symfony 3.3 and uses some kind of "proxy" class to forward events but keeping the listener lazy... I'm not really happy with the solution, but do not see an easy way to do it.

A similar approach can be to use symfony "lazy" services (using https://symfony.com/doc/current/service_container/lazy_services.html), this solution might work with older symfony versions, but will require the proxy library

Update:
the previous implementation had the side effect that public services become not-lazy, now if a service is private, will not be lazy. of course this can be avoided using https://symfony.com/doc/current/service_container/lazy_services.html

[goetas]

@bgaleotti thanks :)