* [**Breaking Change**] Optimize single trace query performance by customizing routing in ElasticSearch. SkyWalking trace segments and Zipkin spans are using trace ID for routing.
* [Optional] Optimize single trace query performance by customizing routing in ElasticSearch. SkyWalking trace segments and Zipkin spans are using trace ID for routing. This is OFF by default, controlled by `storage/elasticsearch/enableCustomRouting`.