anchor.diff:  How can we write this data structure on disk or send it over the wire to log collection tool?
   We have to serialize it.
   For a human being, a simple text format as shown above is readable enough.
  -However, for a machine, it is a just a word soup without any structure.
  +However, for a machine, this is a just a word soup without any structure.
   In order to send structured logs to a log collection tool, 
   and take advantage of this structure (search by user, by thread...), 
   we must use a structured format like JSON.
  
positive.code: 	demoLogger.info("Hello world!");
  }
  ----
  Hopefully, this kind of code won't make its way in your business code because it is usually hidden in an interceptor like a Servlet filter, a Spring aspect or a JAXRS interceptor. In Logback, there is a `MDCInsertingServletFilter` class which can be used as an example.
  
  
  == JSON logging with Logback
  
negative.code: Compared to the Syslog, another popular log format, the JSON format
  
  * Can properly handle  multi-line logs like stack traces/call traces or messages containing line separators (wanted or not)
  * Is a versatile format and can have custom fields like user Id, transaction Id 
  * Is more verbose, so compression (GZip or the like) may be required to reduce the weight
  
  Most popular log collection tools likes Filebeat, Graylog, Fluentd already use some kind of compressed JSON format under the hood.
  