make FileReader to close fd using RAII

[zhengbuqian]

/kind bug

issue: #1004
#1004

[sre-ci-robot]

@zhengbuqian: The label(s) kind/fix cannot be applied, because the repository doesn't have them.

In response to this:

/kind fix
issue: #1004

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[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: zhengbuqian

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• OWNERS [zhengbuqian]

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[mergify]

@zhengbuqian 🔍 Important: PR Classification Needed!

For efficient project management and a seamless review process, it's essential to classify your PR correctly. Here's how:

1. If you're fixing a bug, label it as kind/bug.
2. For small tweaks (less than 20 lines without altering any functionality), please use kind/improvement.
3. Significant changes that don't modify existing functionalities should be tagged as kind/enhancement.
4. Adjusting APIs or changing functionality? Go with kind/feature.

For any PR outside the kind/improvement category, ensure you link to the associated issue using the format: “issue: #”.

Thanks for your efforts and contribution to the community!.

[foxspy]

/lgtm

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.03%. Comparing base (3c46f4c) to head (d72e7e0).
Report is 279 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##           main    #1005       +/-   ##
=========================================
+ Coverage      0   74.03%   +74.03%     
=========================================
  Files         0       82       +82     
  Lines         0     6960     +6960     
=========================================
+ Hits          0     5153     +5153     
- Misses        0     1807     +1807     

see 82 files with indirect coverage changes

[alexanderguzhva]

/lgtm

[alexanderguzhva]

issue: #1004

[foxspy]

/kind improvement