anchor.diff:  
   [source,js]
   --------------------------------------------------
  -$ curl -XPUT 'localhost:9200/_bench/?pretty=true' -d
  -{
  +$ curl -XPUT 'localhost:9200/_bench/?pretty=true' -d '{
       "name": "my_benchmark",
       "num_executor_nodes": 1,
       "percentiles" : [ 25, 50, 75 ],
  
positive.code: 
  [source,js]
  --------------------------------------------------
  $ curl -XPUT 'localhost:9200/_bench/?pretty=true' -d
  '{
      "name": "my_benchmark",
      "competitors": [ {
          "name": "my_competitor",
  
negative.code:             "fields": ["title"]
          }
      } ]
  }'
  --------------------------------------------------
  
  Response:
  