internal static void IndexIEnumerable<TDocument>(
    this ElasticClient client,
    string indexName,
    IEnumerable<TDocument> source,
    int? batchSize = null,
    int? maxDegreeOfParallelism = null,
    TimeSpan? backOffTime = null,
    int? backOffRetries = null,
    Action<int> onNextBatchExecuted = null,
    CancellationToken cancellationToken = default)
    where TDocument : class
{
    cancellationToken.ThrowIfCancellationRequested();
    if (source == null)
        throw new ArgumentNullException(nameof(source),
            "Требуется указать перечисление, содержащее индексируемые объекты");

    var actualBatchSize = batchSize ?? 1000;

    var actualMaxDegreeOfParallelism = maxDegreeOfParallelism ?? GetMaxDegreeOfParallelism();
    var actualBackOffTime = backOffTime ?? TimeSpan.FromSeconds(30);
    var actualBackOffRetries = backOffRetries ?? 10;
    var observable = client.BulkAll(
        source,
        bulkAllDescriptor => bulkAllDescriptor
            .Index(indexName)
            .MaxDegreeOfParallelism(actualMaxDegreeOfParallelism)
            .BackOffTime(new Time(actualBackOffTime))
            .BackOffRetries(actualBackOffRetries)
            .Size(actualBatchSize)
            .RefreshOnCompleted(),
        cancellationToken);

    var totalBatchesIndexed = 0;
    Action<IBulkAllResponse> bulkResponseAction = response => { };
    if (onNextBatchExecuted != null)
        bulkResponseAction = response =>
        {
            var currentIndexedDocs = Interlocked.Increment(ref totalBatchesIndexed) * actualBatchSize;
            onNextBatchExecuted(currentIndexedDocs);
        };

    var waitHandle = new ManualResetEvent(false);
    Exception exception = null;
    var observer = new BulkAllObserver(
        onError: e =>
        {
            exception = e;
            waitHandle.Set();
        },
        onNext: bulkResponseAction,
        onCompleted: () => { waitHandle.Set(); });
    observable.Subscribe(observer);
    waitHandle.WaitOne();
    if (exception != null)
        throw exception;
}