abstracted the client.do retry loop to it's own func

[josephbergevin]

closes #30

[codecov]

Codecov Report

Merging #32 into master will increase coverage by 0.22%.
The diff coverage is 58.33%.

@@            Coverage Diff             @@
##           master      #32      +/-   ##
==========================================
+ Coverage   38.98%   39.21%   +0.22%     
==========================================
  Files           7        7              
  Lines         454      459       +5     
==========================================
+ Hits          177      180       +3     
- Misses        250      251       +1     
- Partials       27       28       +1

Impacted Files	Coverage Δ
client.go	52.99% <58.33%> (+0.31%)	⬆️

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