Cannot generate examples from xml <example> tag

I have made changes based on the sample project https://github.com/RicoSuter/NSwag/tree/master/samples/NSwag.Sample.NetOwinMiddleware the package versions are:

  <package id="NJsonSchema" version="10.1.12" targetFramework="net472" />
  <package id="NSwag.AspNet.Owin" version="13.4.2" targetFramework="net472" />
  <package id="NSwag.Core" version="13.4.2" targetFramework="net472" />
  <package id="NSwag.Generation" version="13.4.2" targetFramework="net472" />
  <package id="NSwag.Generation.WebApi" version="13.4.2" targetFramework="net472" />
  <package id="NSwag.SwaggerGeneration" version="12.3.0" targetFramework="net472" />
  <package id="NSwag.SwaggerGeneration.WebApi" version="12.3.0" targetFramework="net472" />
  <package id="Owin" version="1.0" targetFramework="net472" />
  <package id="System.Buffers" version="4.4.0" targetFramework="net472" />
  <package id="System.Xml.XPath" version="4.3.0" targetFramework="net472" />

I try to add example to model Product like https://github.com/RicoSuter/NJsonSchema/wiki/XML-Documentation#define-examples does. here is the codes.

    /// <summary>
    /// product
    /// </summary>
    /// <example>
    ///{
    ///     "id":5,
    ///     "name":"abc",
    ///     "category":"food",
    ///     "price":10.0
    ///}
    /// </example>
    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Category { get; set; }
        public decimal Price { get; set; }
    }

app.UseSwaggerUi3(typeof(Startup).Assembly, settings =>
            {
                // configure settings here
                // settings.GeneratorSettings.*: Generator settings and extension points
                // settings.*: Routing and UI settings
                settings.GeneratorSettings.DefaultUrlTemplate = "api/{controller}/{id?}";
                settings.GeneratorSettings.GenerateExamples = true;
                settings.GeneratorSettings.AllowNullableBodyParameters = false;
            });

However, I could not see the example in the swagger.json.

"Product": {
      "type": "object",
      "required": [
        "Id",
        "Price"
      ],
      "properties": {
        "Id": {
          "type": "integer",
          "format": "int32"
        },
        "Name": {
          "type": "string"
        },
        "Category": {
          "type": "string"
        },
        "Price": {
          "type": "number",
          "format": "decimal"
        }
      }
    }

I have no idea what I'm missing. I have searched a lot of discussion about the missing examples. But it seems I have everything to make it work but it doesn't. Please help to look at this question, I appreciate it.

RicoSuter / NJsonSchema

Cannot generate examples from xml <example> tag #1179