chore(*): add metric

[cheney-lin]

What type of PR is this?

Enhancements

What this PR does / why we need it:

Which issue(s) this PR fixes:

Special notes for your reviewer:

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 55.36%. Comparing base (1521631) to head (71a9c10).
Report is 2 commits behind head on main.

Files	Patch %	Lines
pkg/agent/resourcemanager/fetcher/manager.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #521      +/-   ##
==========================================
- Coverage   55.70%   55.36%   -0.35%     
==========================================
  Files         552      552              
  Lines       59368    59381      +13     
==========================================
- Hits        33073    32876     -197     
- Misses      22854    23071     +217     
+ Partials     3441     3434       -7     

Flag	Coverage Δ
unittest	55.36% <0.00%> (-0.35%)	⬇️

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