How to use include_named_queries_score with NEST client

Question

Using the .NET Nest client for elastic search, how do I get it actually spit out the score for a named query?

I can set a name on part of my query, and it'll generate an elastic query that might look something like this:

"query": {
   "bool": {
      "must": [
          {
             "bool": {
                "_name": "myMatches",
                "minimum_should_match":1,
                "should": [
                    {
                       "terms": {
                          "foo":["a"]
                       }
                    },
                    {
                       "terms": {
                          "bar":["b"]
                       }
                    }
                ]
             }
          },
          // multiple other clauses
      ]  
   }
}

And in the kibana console, it'll spit out hits including something this:

        "matched_queries": [
          "myMatches"
        ]

But if I include this query string:

_search?include_named_queries_score

Then it'll give me scores for that named query:

        "matched_queries": {
          "myMatches":1
        }

But in the NEST client, I'm only getting an array of names of matched named queries, there doesn't seem to be a way to get it to include the include_named_queries_score and actually get the score in the result. Am I missing something?

            var search = client.SearchAsync<MyPosts>(s => s
                .Source(src => src
                    .Includes(i => i.Fields(fields))
                )
                .Query(q => q && filterQuery)
                .From(from)
                .Size(size)
                .TrackTotalHits(true)
                , cancel);

There doesn't seem to be a .IncludeNamedQueryScore or similar. Is there support for this somewhere? Or would I have to hack around adding it to the generated query url and then handle the raw JSON response myself to make this work?