anchor.diff:      "settings": {
         "index.lifecycle.name": "my-lifecycle-policy"
       }
  +  },
  +  "_meta": {
  +    "my-meta-field": "foo"
     }
   }
   
  
positive.code:         }
        ],
        "generation": 2,
        "status": "GREEN",
        "template": "my-index-template",
        "ilm_policy": "my-lifecycle-policy",
  
negative.code: (integer)
  Current <<data-streams-generation,generation>> for the data stream. This number
  acts as a cumulative count of the stream's rollovers, starting at `1`.
  
  `_meta`::
  (object)
  Custom metadata for the stream, copied from the `_meta` object of the
  stream's matching <<create-a-data-stream-template,index template>>. If empty,
  the response omits this property.
  
  `status`::
  (string)
  