Another important place where access metadata needs to be considered is AccessResultInterface. If you remember from the previous chapter, objects implementing this interface are used consistently to represent access to a certain resource. On top of that, they can also contain cacheability metadata. This is because access may depend on certain data that can change with an impact on the access result itself. Since Drupal tries to cache access as well, we need to inform it of these dependencies.
A good example to see this in action is our HelloWorldAccess service where we dynamically check access to our hello_world.hello route. So instead of simply returning the AccessResultInterface, we add cacheable dependencies to it ...
