anchor.diff:  curl -XGET 'http://localhost:9200/twitter/tweet/1?_source_include=*.id&_source_exclude=entities'
   --------------------------------------------------
   
  -If only want to specify includes, you can use a shorter notation:
  +If you only want to specify includes, you can use a shorter notation:
   
   [source,js]
   --------------------------------------------------
  
positive.code: 
  [source,js]
  --------------------------------------------------
  curl -XHEAD 'http://localhost:9200/twitter/tweet/1/_source'
  --------------------------------------------------
  
  [float]
  
negative.code: 
  The above result includes the `_index`, `_type`, and `_id` of the
  document we wish to retrieve, including the actual source of the
  document that was indexed if it could be found (as indicated by the
  `found` field in the response).
  
  The API also allows to check for the existence of a document using
  `HEAD`, for example:
  
  [source,js]
  --------------------------------------------------
  curl -I 'http://localhost:9200/twitter/tweet/1'
  --------------------------------------------------
  
  [float]
  