mike-burns/aeson — comment on commit 6d16f551549a667fef618b2dde94d0bc088d5ca8
File:  line 0
By hvr:

btw, padding with `0`s could be easily accomplished by testing for non-zero milliseconds (which would safe us from calling `formatTime "%Q"` in the first place for whole-seconds) and then just using `take 4 $ formatTime ... "%Q" t ++ "000"`