Proposal: make default unit nanosecond

[zaquestion]

Its somewhat non-intuitive when setting a delay which takes a time.Duration that the units are in microseconds. Its easy to write code like this and think its valid.

       err = retry.Do(func() error {
               return foo()
       }, retry.Attempts(3), retry.Delay(time.Second))

[codyaray]

+💯

This is a huge bug in the usability of this library.

I just spent a couple hours tracking down why my app was appearing to just hang. My configuration of retry.Attempts(5), retry.Delay(1*time.Minute) was calling time.Sleep for 16h40m0s.

See https://play.golang.org/p/hqx9XFcPATj

A time.Duration is represented in nanoseconds. The fact that this library multiplies by microseconds by default completely breaks the standard time math in golang.

[JaSei]

Good point, thank you... What you mean about change API to delay and unit merge to one attribute delay which will be parsed by time.ParseDuration ?

[codyaray]

I think the api should just take a delay parameter of type time.Duration and there shouldn't be a separate unit field.

[JaSei]

#11