title: What Elasticsearch client does Spring-Data-Elasticsearch use under the hood?
body: <p>I want to use Spring Data Elasticsearch in my project and I saw this:</p>
  
  <blockquote>The well known TransportClient is deprecated as of Elasticsearch 7.0.0 and is expected to be removed in Elasticsearch 8.0. </blockquote>
  
  <p>My approach is to only use Spring Data Elasticsearch to do CRUD operations (ORM-like), and High Level REST Client for searching and all the rest.
  So I want to know which client is the ElasticsearchRepository using to perform its operations, and if the code will no longer be valid in version 8.0 of Elasticsearch.<br>
  Is it still a good decision to use version 3.1.5?</p>