How can I pull a json element from a Find document of type WebContent? For example, we have this json for a WebContent document crawled in from a Find connector :

  "SearchSourceName$$string": "Press Releases2",
    "_id": "e7f8ceb345c3f98fe6b0cebe61b14b6a305b40b3",
    "$type": "EPiServer.Find.Framework.WebContent, EPiServer.Find.Framework",
    "SearchMetaData": {
        "viewport": {
            "StringValue$$string": "width=device-width, initial-scale=1",
            "$type": "EPiServer.Find.IndexValue, EPiServer.Find",
            "___types": [
                "EPiServer.Find.IndexValue",
                "System.Object"
            ]
        },

I am doing this from a scheduled job:

    var rs = client.Search().WildCardQuery("*2013*", x => x.SearchText).GetResult();
        foreach (var ri in rs)
            {    
            
                // here I would like to get the "_id" in the json
    
            }