How to use optional parameters?

How to use C# Optional Parameters In Search Query?

 public virtual List<Product> SearchProducts(
          bool? isFeatured = null,
          bool? sameDayShipping = null,
          bool? isMostAdvantage = null,
          bool? overridePublished = null)
        {
            var searchResponse = client.Search<Product>(s => s
               .Index("product")
                // How can I add non-null optional parameters?
           );
        }

What version of NEST are you using?

Hi,

Elastic version information is detailed below.

{
"name": "LocalNode",
"cluster_name": "elasticsearch",
"cluster_uuid": "UmPUC8uoS8yl1CttzX2zaA",
"version": {
"number": "6.2.2",
"build_hash": "10b1edd",
"build_date": "2018-02-16T19:01:30.685723Z",
"build_snapshot": false,
"lucene_version": "7.2.1",
"minimum_wire_compatibility_version": "5.6.0",
"minimum_index_compatibility_version": "5.0.0"
},
"tagline": "You Know, for Search"
}

That's the version of Elasticsearch you're running against. What version of the NEST .NET client are you using to communicate with Elasticsearch?