NEST: Using RequestResponseSerializer to deserialize to MultiSearchResponse

Question

I'm using NEST to send a manual query to the multisearch API, with the body as NDJSOn as docuemnted in Elastic's docs:

var query = @"
...
";
StringResponse response = await _elastic.LowLevel.MultiSearchAsync<StringResponse>(indexName, PostData.String(query));

The response is succesful and I'm receiving 200. However, I'd like to serialize it to MultisearchResponse. For regular search queries, I'm using the built-in serializer like so:

var stream = new MemoryStream(Encoding.UTF8.GetBytes(response.Body));
SearchResponse<MetadataDto> searchResponse = _elastic.RequestResponseSerializer.Deserialize<SearchResponse<MetadataDto>>(stream);

However, when trying to do the same and use MultiSearchResponse, it throws: Constructor on type 'Nest.MultiSearchResponseFormatter' not found.:

var stream = new MemoryStream(Encoding.UTF8.GetBytes(response.Body));
MultiSearchResponse multiSearchResponse = _elastic.RequestResponseSerializer.Deserialize<MultiSearchResponse>(stream);
// TODO: Get all the responses using 'multiSearchResponse.GetResponses<T>`.

Why is that happening, or what am I doing wrong?