add retry.Do0

[zhiqiangxu]

The Do and Do2 expects a function that returns (T,error) and (T,U,error) respectively.

This PR adds a Do0 function that accepts a function that returns error only, which is handy in many cases.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.97%. Comparing base (c7ab63b) to head (48700ea).
Report is 17 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #12194      +/-   ##
===========================================
- Coverage    75.19%   74.97%   -0.22%     
===========================================
  Files           49       49              
  Lines         3656     3656              
===========================================
- Hits          2749     2741       -8     
- Misses         734      743       +9     
+ Partials       173      172       -1     

Flag	Coverage Δ
cannon-go-tests	74.97% <ø> (-0.22%)	⬇️

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see 1 file with indirect coverage changes

[ajsutton]

I like the idea, but nothing is actually using it. Are the places in the code that should be updated to use the new Do0 function?

[zhiqiangxu]

I like the idea, but nothing is actually using it. Are the places in the code that should be updated to use the new Do0 function?

It was my code outside that wanted to reuse retry package in the monorepo, but I also find two places in the monorepo that can be refactored to use the Do0.

[ajsutton]

LGTM.