title: Which field matched query in multi_match search in Elasticsearch?
body: <p>I have  query with multi_match in Elasticsearch:</p>
  
  <pre><code>{
    "query": {
      "multi_match": {
        "query": "luk",
        "fields": [
          "xml_string.autocomplete",
          "state"
        ]
      }
    },
    "size": 10,
    "fields": [
      "xml_string",
      "state"
    ]
  }
  </code></pre>
  
  <p>It works great, result returns expected value: </p>
  
  <pre><code>{
    "took": 2,
    "timed_out": false,
    "_shards": {
      "total": 5,
      "successful": 5,
      "failed": 0
    },
    "hits": {
      "total": 1,
      "max_score": 0.41179964,
      "hits": [
        {
          "_index": "documents",
          "_type": "document",
          "_id": "11",
          "_score": 0.41179964,
          "fields": {
            "xml_string": "Lukas bla bla bla",
            "state": "new"
          }
        }
      ]
    }
  }
  </code></pre>
  
  <p>I've searched a lot, but I am not able to find out which field matched the query(if it was xml_string OR state)</p>