v0.5.10: properly drain the timer before use
this might have been the source of various race conditions I saw in the past 😩 references: https://www.reddit.com/r/golang/comments/1inw7nc/anyone_else_seeing_old_unit_tests_that_involve/ https://blogtitle.github.io/go-advanced-concurrency-patterns-part-2-timers/#time-newtimer