kirktrue commented on code in PR #17035:
URL: https://github.com/apache/kafka/pull/17035#discussion_r1817401005


##########
clients/src/main/java/org/apache/kafka/clients/consumer/internals/FetchRequestManager.java:
##########
@@ -65,16 +69,60 @@ protected void maybeThrowAuthFailure(Node node) {
         networkClientDelegate.maybeThrowAuthFailure(node);
     }
 
+    /**
+     * Signals the {@link Consumer} wants requests be created for the broker 
nodes to fetch the next
+     * batch of records.
+     *
+     * @see CreateFetchRequestsEvent
+     * @return Future on which the caller can wait to ensure that the requests 
have been created
+     */
+    public CompletableFuture<Void> createFetchRequests() {
+        CompletableFuture<Void> future = new CompletableFuture<>();
+
+        if (pendingFetchRequestFuture != null) {
+            // In this case, we have an outstanding fetch request, so chain 
the newly created future to be
+            // completed when the "pending" future is completed.
+            pendingFetchRequestFuture.whenComplete((value, exception) -> {
+                if (exception != null) {
+                    future.completeExceptionally(exception);
+                } else {
+                    future.complete(value);
+                }
+            });
+        } else {
+            pendingFetchRequestFuture = future;
+        }
+
+        return future;
+    }
+
     /**
      * {@inheritDoc}
      */
     @Override
     public PollResult poll(long currentTimeMs) {
-        return pollInternal(
+        if (pendingFetchRequestFuture == null) {
+            // If no explicit request for creating fetch requests was issued, 
just short-circuit.
+            return PollResult.EMPTY;
+        }
+
+        try {
+            PollResult result = pollInternal(
                 prepareFetchRequests(),
                 this::handleFetchSuccess,
                 this::handleFetchFailure
-        );
+            );
+            pendingFetchRequestFuture.complete(null);

Review Comment:
   I've moved the `Future`-handling code to `pollInternal()` for consistency. 
LMK what you think.



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