Fix RpcUtils.retry() silently swallowing timeout and max-retry exceptions, returning null

[eye-gu]

close #1877

1. timeoutChecker 类型从 Callable 改为 Function<Long, Boolean>
   原来的代码：timeoutChecker 是 Callable，call() 声明了受检异常，调用方被迫 try-catch 包裹，catch 块 ignored 无差别吞掉了所有异常——包括超时时抛出的 MilvusClientException.

修改为 Function<Long, Boolean>，通过 timeoutChecker.apply(System.currentTimeMillis()) 调用，无需捕获受检异常，超时异常能正确向上传播

2. 移除包裹 k >= maxRetryTimes 退出逻辑的外层 try-catch
   原来的代码：达到最大重试次数后抛出的 MilvusClientException 被外层 try { ... throw ... } catch (Exception ignored) {} 吞掉，导致循环正常结束并 return null。

修改为只对sleep进行catch

3. 退避 sleep 前预判是否会超时，提前退出
   原来的代码：退避间隔直接 sleep，没有做任何预判。当指数退避乘数较大时，最后一次 sleep 可能使累计耗时远超 maxRetryTimeoutMs.减少无意义的等待

[sre-ci-robot]

Welcome @eye-gu! It looks like this is your first PR to milvus-io/milvus-sdk-java 🎉

[Copilot]

Pull request overview

Fixes issue #1877 where RpcUtils.retry() silently swallowed MilvusClientException thrown for timeout and max-retry exit paths, causing the method to return null instead of surfacing the failure. Also adds early-exit logic that detects when the next backoff sleep would push the total elapsed time past maxRetryTimeoutMs, avoiding unnecessary waits.

Changes:

• Change timeoutChecker from Callable<Boolean> to Function<Long, Boolean> so the caller no longer needs a try/catch (Exception ignored) wrapper that hid the timeout exception.
• Remove the outer try/catch (Exception ignored) around the k >= maxRetryTimes branch so the terminal MilvusClientException actually propagates; only Thread.sleep is now wrapped.
• Predict whether the next backoff sleep will exceed maxRetryTimeoutMs and throw a TIMEOUT exception early, plus new RpcUtilsTest covering timeout, max-retry, and slow-call scenarios.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
sdk-core/src/main/java/io/milvus/v2/utils/RpcUtils.java	Rework retry-loop exception handling so timeout/max-retry exceptions propagate; add pre-sleep timeout prediction.
sdk-core/src/test/java/io/milvus/v2/utils/RpcUtilsTest.java	New unit tests covering early backoff exit, max retry exhaustion, and slow-call timeout.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[yhmo]

@eye-gu
感谢修正了这个问题。

[yhmo]

/lgtm
/approve

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: eye-gu, yhmo

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [yhmo]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment