anchor.diff:          "metrics": {
             "m": 2.718280076980591,
             "i": -12,
  -          "d": "2019-12-31T00:12:12.000Z"
  +          "d": "2019-12-31T00:12:12.000Z",
  +          "t.keyword": "chicken"
           }
         } ]
       }
  
positive.code: The `sort` field in the metric request functions exactly the same as the `sort` field in the
  <<sort-search-results, search>> request except:
  
  * It can't be used on <<binary,binary>>, <<flattened,flattened>> or <<text,text>> fields.
  * It only supports a single sort value so which document wins ties is not specified.
  
  The metrics that the aggregation returns is the first hit that would be returned by the search
  
negative.code: `metrics` selects the fields of the "top" document to return. You can request
  a single metric with something like `"metric": {"field": "m"}` or multiple
  metrics by requesting a list of metrics like `"metric": [{"field": "m"}, {"field": "i"}`.
  The fields can be <<number,numbers>>, <<keyword,keywords>>, or <<ip,ips>>.
  Here is a more complete example:
  
  [source,console,id=search-aggregations-metrics-top-metrics-list-of-metrics]
  