Clarify load balance behavior if array of hosts is used

I've seen the question, on how the output load balances, coming up every now and then and the docs should have the answer.
I'd still like a logstash developer to review and double check that it still is Round-robin per bulk in the current version of the plugin. 
My assumption is based on #274 and #493 (comment), but the first one is from 2015 and the second onw is from 2018, but with Logstash 2.4.

Author: jakommo

Diff for: docs/index.asciidoc

@@ -344,7 +344,7 @@ If you have custom firewall rules you may need to change this
   * Value type is <<uri,uri>>
   * Default value is `[//127.0.0.1]`
 
-Sets the host(s) of the remote instance. If given an array it will load balance requests across the hosts specified in the `hosts` parameter.
+Sets the host(s) of the remote instance. If given an array it will load balance requests across the hosts specified in the `hosts` parameter (Round-robin per bulk request sent to Elasticsearch).
 Remember the `http` protocol uses the http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-http.html#modules-http[http] address (eg. 9200, not 9300).
     `"127.0.0.1"`
     `["127.0.0.1:9200","127.0.0.2:9200"]`