Whilst developing with Elasticsearch using NEST, it can be extremely valuable to see the requests that NEST generates and sends to Elasticsearch, as well as the responses returned.
There are a couple of popular ways of capturing this information
In addition to logging requests and responses, Elasticsearch 5.0+ also sends back warning headers in the response, to notify you if you are using a feature that is marked as deprecated.
When things are going awry, you want to be provided with as much information as possible, to resolve the issue!
Elasticsearch.Net and NEST provide an audit trail and debug information to help get you back on the happy path.