ElasticSearch & attachment type (NEST C#)

I'm trying to index a pdf document with elasticsearch/NEST.

The file is indexed but search results returns with 0 hits.

I need the search result to return only the document Id and the highlight result

(without the base64 content)

Here is the code:

I'll appreciate any help here,

Thanks,

class Program
{
    static void Main(string[] args)
    {
        // create es client
        string index = "myindex";

        var settings = new ConnectionSettings("localhost", 9200)
            .SetDefaultIndex(index);
        var es = new ElasticClient(settings);

        // delete index if any
        es.DeleteIndex(index);

        // index document
        string path = "test.pdf";
        var doc = new Document()
        {
            Id = 1,
            Title = "test",
            Content = Convert.ToBase64String(File.ReadAllBytes(path))
        };

        var parameters = new IndexParameters() { Refresh = true };
        if (es.Index<Document>(doc, parameters).OK)
        {
            // search in document
            string query = "semantic"; // test.pdf contains the string "semantic"

            var result = es.Search<Document>(s => s
                .Query(q =>
                    q.QueryString(qs => qs
                        .Query(query)
                    )
                )
                .Highlight(h => h
                    .PreTags("<b>")
                    .PostTags("</b>")
                    .OnFields(
                      f => f
                        .OnField(e => e.Content)
                        .PreTags("<em>")
                        .PostTags("</em>")
                    )
                )
            );

            if (result.Hits.Total == 0)
            {
            }
        }
    }
}

[ElasticType(
    Name = "document",
    SearchAnalyzer = "standard",
    IndexAnalyzer = "stan