override def send(req: ElasticRequest, callback: Either[Throwable, HttpResponse] => Unit): Unit
Sends the given request to elasticsearch.
Sends the given request to elasticsearch.
Implementations should invoke the callback function once the response is known.
The callback function should be invoked with a HttpResponse for all requests that received a response, including 4xx and 5xx responses. The callback function should only be invoked with an exception if the client could not complete the request.