Fix bench number

[guonaihong]

see #226

[codecov-commenter]

Codecov Report

Merging #227 into master will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #227      +/-   ##
==========================================
- Coverage   92.60%   92.59%   -0.01%     
==========================================
  Files          41       41              
  Lines        1919     1918       -1     
==========================================
- Hits         1777     1776       -1     
  Misses         96       96              
  Partials       46       46              

Impacted Files	Coverage Δ
bench/task.go	87.65% <ø> (-0.16%)	⬇️

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