anchor.diff:  
   This annotation cannot be used on a method returning `void`.
   
  +[NOTE]
  +====
  +Quarkus is able to also cache `null` values unlike the underlying Caffeine provider.
  +See <<negative-cache,more on this topic below>>.
  +====
  +
   === @CacheInvalidate
   
   Removes an entry from the cache.
  
positive.code:     }
  }
  ----
  <1> This method can be used to force a refresh of the cache entry corresponding to the given key. 
  <2> This method will invalidate all entries from the `foo` and `bar` caches with a single call.
  
negative.code: You should get an answer two seconds later since two of the requested days were already loaded in the cache.
  
  You can also try calling the same URL with a different city and see the cache in action again.
  The first call will take six seconds and the following ones will be answered immediately.
  
  Congratulations! You just added application data caching to your Quarkus application with a single line of code!
  
  