Why is Bulk Insert not working in Elastic Search?

Question

C++ / C#

Hello!
I use Nest to communicate with ElasticSearch (I took Nest from the NuGet repositories). .NET Framework 4, x86. I'm trying to add a document using the Bulk method like this:

namespace NestTestCSharp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {

        var client = new ElasticsearchClient();


        var p = new Phrase
        {
            Id = 1,
            Name = "скачать1"
        };


       var descriptor = new BulkDescriptor();

        descriptor.Index<Phrase>(op => op
            .Document(p)
        );

        
        var index = client.Bulk("phrases", "phrase", descriptor);

        }
    }

    class Phrase
    {
        public long Id { get; set; }
        public string Name { get; set; }
    }
}

I get an empty Request and a response like:

{StatusCode: 400, 
  Method: POST, 
  Url: http://localhost:9200/phrases/phrase/_bulk, 
  Request: {}, 
  Response: <Response stream not captured or already read to completion by serializer>
  ExceptionMessage: Validation Failed: 1: no requests added;
   StackTrace: }

Tell me what could be the problem? The code is copied from the official source with minimal changes. I twisted it in every way, but I just can’t add data in batches. Data one by one through client.Index is added normally.
PS I tried, including in this way:

var request = new BulkRequest()
        {
            Refresh = true,
            Consistency = Consistency.One,
            Operations = new List<IBulkOperation>
    {
        { new BulkIndexOperation<Phrase>(p) { Id= "1"} }
   }
        };

        var response = client.Bulk(request);

An error is thrown:

Метод может быть вызван только для метода, для которого значение Type.IsGenericParameter является true.