[ISSUE #6337]🚀Add producer batch send examples

[mxsm]

Which Issue(s) This PR Fixes(Closes)

• Fixes [Feature🚀] Add producer batch send examples #6337

Brief Description

How Did You Test This Change?

Summary by CodeRabbit

• Documentation
  • Added a comprehensive batch-send example demonstrating eight batch-sending patterns for the RocketMQ producer (basic, timeout variants, specific-queue targeting, and callback handling).
  • Registered the new example so it appears alongside existing project examples for easy discovery and usage.

[rocketmq-rust-bot]

🔊@mxsm 🚀Thanks for your contribution🎉！

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Note

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[coderabbitai]

Walkthrough

Adds a new producer batch-send example: a Cargo.toml example entry plus a new Rust example implementing eight batch-send scenarios (variations of timeout, queue targeting, and callbacks).

Changes

Cohort / File(s)	Summary
Configuration rocketmq-example/Cargo.toml	Adds a [[example]] entry named producer-batch-send pointing to examples/producer/batch_send.rs.
Producer example rocketmq-example/examples/producer/batch_send.rs	New example file exposing constants (PRODUCER_GROUP, DEFAULT_NAMESRVADDR, TOPIC, TAG, TIMEOUT_MS) and pub async fn main(), demonstrating eight batch-send scenarios: basic, timeout, specific-queue, queue+timeout, callback variants, and shutdown flow.

Sequence Diagram(s)

sequenceDiagram
    participant Example
    participant Producer
    participant NameServer
    participant Broker

    Example->>Producer: build & start producer
    Producer->>NameServer: fetch topic routes / queues
    NameServer-->>Producer: return queues
    Example->>Producer: invoke batch_send / batch_send_with_callback (with optional queue/timeout)
    Producer->>Broker: send batch request
    Broker-->>Producer: send response / ack
    Producer-->>Example: return result or invoke callback
    Example->>Producer: shutdown
    Producer-->>Broker: cleanup connections

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• [ISSUE #6335]🚀Add producer basic send examples #6336 — Adds a producer example file with the same public constants and pub async fn main(), likely a related or duplicate example addition.

Suggested reviewers

• TeslaRustor
• SpaceXCN
• rocketmq-rust-bot

Poem

🐰 In burrows deep I nibble code,

Eight batches launched along the road,
Queues and callbacks, tidy and neat,
Messages hop to every seat,
A rabbit cheers — producer complete! 🎉

🚥 Pre-merge checks | ✅ 6

✅ Passed checks (6 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: adding producer batch send examples, which matches the file additions and Cargo.toml entry.
Linked Issues check	✅ Passed	The PR adds producer batch send examples with eight scenarios as intended by issue #6337, fulfilling the feature requirement.
Out of Scope Changes check	✅ Passed	All changes are directly related to adding producer batch send examples; no unrelated modifications detected.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Merge Conflict Detection	✅ Passed	✅ No merge conflicts detected when merging into main

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feat-6337

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@rocketmq-example/examples/producer/batch_send.rs`:
- Line 159: The CI fails due to rustfmt violations in the producer example; run
`cargo fmt --all` and reformat the multi-line function signature
`batch_send_to_queue` and its call sites so they comply with rustfmt,
specifically reflow the `send_batch_to_queue_with_timeout` and
`send_batch_with_callback` invocations (and other multi-line calls around those
locations) to use the standard Rust multiline call formatting; ensure
`DefaultMQProducer` usage and argument lists are line-wrapped consistently so
`cargo fmt` passes.

🧹 Nitpick comments (2)

rocketmq-example/examples/producer/batch_send.rs (2)

232-239: Consider extracting the duplicated callback closure.

The identical callback closure is repeated four times. For an example file, this is acceptable for readability, but you could reduce duplication with a small helper function.

♻️ Optional: extract shared callback

+fn batch_send_callback(result: Option<&SendResult>, error: Option<&dyn std::error::Error>) {
+    match (result, error) {
+        (Some(r), None) => println!("   Callback: Success - {:?}", r),
+        (None, Some(e)) => println!("   Callback: Error - {}", e),
+        _ => println!("   Callback: Unknown state"),
+    }
+}

Then use batch_send_callback in place of each inline closure.

Also applies to: 266-273, 300-307, 334-341

---

54-56: Silent skip when no queues are available.

If fetch_publish_message_queues returns an empty list, scenarios 3, 4, 7, and 8 are silently skipped with no indication to the user. Consider printing a warning so the user understands why those examples didn't run.

💡 Suggested improvement

     let queues = producer.fetch_publish_message_queues(TOPIC).await?;
     let target_queue = queues.first().cloned();
+    if target_queue.is_none() {
+        println!("   ⚠ No queues available for topic '{}', queue-specific examples will be skipped.", TOPIC);
+    }

[rocketmq-rust-bot]

LGTM - All CI checks passed ✅