Added comment

Signed-off-by: Nils Bandener <[email protected]>

Author: nibix

src/integrationTest/java/org/opensearch/test/framework/data/TestData.java

@@ -235,6 +235,7 @@ public void putDocuments(Client client, String name, int rolloverAfter) {
                 }
 
                 if (i > nextRollover) {
+                    // This creates several generations of backing indices for data streams
                     client.admin().indices().rolloverIndex(new RolloverRequest(name, null));
 
                     nextRollover += rolloverAfter;