Add method

server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java

@@ -2113,7 +2113,7 @@ public void flush(boolean force, boolean waitIfOngoing, ActionListener<FlushResu
                 // Only flush if (1) Lucene has uncommitted docs, or (2) forced by caller, or (3) the
                 // newly created commit points to a different translog generation (can free translog),
                 // or (4) the local checkpoint information in the last commit is stale, which slows down future recoveries.
-                boolean hasUncommittedChanges = indexWriter.hasUncommittedChanges();
+                boolean hasUncommittedChanges = hasUncommittedChanges();
                 if (hasUncommittedChanges
                     || force
                     || shouldPeriodicallyFlush()
@@ -2173,6 +2173,10 @@ public void flush(boolean force, boolean waitIfOngoing, ActionListener<FlushResu
         waitForCommitDurability(generation, listener.map(v -> new FlushResult(true, generation)));
     }
 
+    protected boolean hasUncommittedChanges() {
+        return indexWriter.hasUncommittedChanges();
+    }
+
     private void refreshLastCommittedSegmentInfos() {
         /*
          * we have to inc-ref the store here since if the engine is closed by a tragic event