public void ModifyItemPacked(string itemJson = null)
        {
            AssertError(ReindexerBinding.reindexer_open_namespace(_rx, DataTestNamespace.GetHandle(),
                                                                  new StorageOpts {
                options = StorageOpt.kStorageOptCreateIfMissing | StorageOpt.kStorageOptEnabled
            },
                                                                  _ctxInfo));

            var indexDefJson = JsonSerializer.ToJsonString(
                new Index
            {
                Name      = "Id",
                IsPk      = true,
                FieldType = FieldType.Int64,
                IndexType = IndexType.Hash,
                JsonPaths = new List <string> {
                    "Id"
                }
            }, Utf8Json.Resolvers.StandardResolver.ExcludeNull);

            AssertError(ReindexerBinding.reindexer_add_index(_rx, DataTestNamespace.GetHandle(), indexDefJson.GetHandle(), _ctxInfo));
            indexDefJson = JsonSerializer.ToJsonString(
                new Index
            {
                Name      = "Guid",
                IsPk      = false,
                FieldType = FieldType.String,
                IndexType = IndexType.Hash,
                JsonPaths = new List <string> {
                    "Guid"
                }
            }, Utf8Json.Resolvers.StandardResolver.ExcludeNull);
            AssertError(ReindexerBinding.reindexer_add_index(_rx, DataTestNamespace.GetHandle(), indexDefJson.GetHandle(), _ctxInfo));

            var rsp = ReindexerBinding.reindexer_select(_rx,
                                                        $"SELECT \"indexes.name\" FROM #namespaces WHERE name = \"{DataTestNamespace}\"".GetHandle(),
                                                        1, new int[0], 0, _ctxInfo);

            if (rsp.err_code != 0)
            {
                Assert.AreEqual(null, (string)rsp.@out);
            }
            Assert.AreNotEqual(UIntPtr.Zero, [email protected]_ptr);

            var(json, offsets, explain) = BindingHelpers.RawResultToJson(rsp.@out, "items", "total_count");
            var indexNames = JsonSerializer.Deserialize <ItemsOf <Namespace> >(json).Items.SelectMany(n => n.Indexes.Select(i => i.Name)).ToList();

            CollectionAssert.Contains(indexNames as ICollection, "Id");
            CollectionAssert.Contains(indexNames as ICollection, "Guid");

            using (var ser1 = new CJsonWriter())
            {
                ser1.PutVString(DataTestNamespace);
                ser1.PutVarCUInt((int)DataFormat.FormatJson); //format
                ser1.PutVarCUInt((int)ItemModifyMode.Upsert); //mode
                ser1.PutVarCUInt(0);                          //stateToken
                ser1.PutVarCUInt(0);                          //len(precepts)

                reindexer_buffer.PinBufferFor(ser1.CurrentBuffer, args =>
                {
                    using (var data = reindexer_buffer.From(Encoding.UTF8.GetBytes(itemJson ?? $"{{\"Id\":1, \"Guid\":\"{Guid.NewGuid()}\"}}")))
                    {
                        rsp = ReindexerBinding.reindexer_modify_item_packed(_rx, args, data.Buffer, _ctxInfo);
                        if (rsp.err_code != 0)
                        {
                            Assert.AreEqual(null, (string)rsp.@out);
                        }

                        Assert.AreNotEqual(UIntPtr.Zero, [email protected]_ptr);

                        var reader         = new CJsonReader(rsp.@out);
                        var rawQueryParams = reader.ReadRawQueryParams();

                        Assert.AreEqual(1, rawQueryParams.count);

                        reader.ReadRawItemParams();

                        if ([email protected]_ptr != UIntPtr.Zero)
                        {
                            AssertError(ReindexerBinding.reindexer_free_buffer(rsp.@out));
                        }
                    }
                });
            }
        }