We could avoid JSON parsing altogether in some cases. For instance, right now when we create a document and receive a HTTP status 200 response, we parse the response, but we don't do anything about it. We probably could avoid this parsing. Not sure the performance impact would be high though, since we try to bulk such requests, and when receiving a bulk response we definitely need to parse the response (it contains the HTTP status code for each bulked request).
Let's investigate a bit whether 1) JSON parsing has a big impact on overall performance and 2) we can implement some kind of lazy parsing easily.