anchor.diff:  The first argument (client filter) will be applied during serialization of the client object to the server. The second Object (server filter)
   will be applied during serialization of the server result from the server to the client. This second one is converted as a String and passed
   to the server as HTTP header. It is then transmitted from the request to the response handler by a Spring `ResponseBodyAdvice`.
  - 
positive.code: 
  Of course in most cases you will use more than one `RestTemplate` so you will have to share the same `SpearalFactory`
  accross the whole application.
  It's recommended to build the `SpearalFactory` inside a singleton and reuse it everywhere in the app :
  
  [source,java]
  ----
  
negative.code:     }
      
      @Bean
      public PlatformTransactionManager transactionManager(EntityManagerFactory emf) {
      	...
      }
  }
  