periodic/periodic.go
func TickerGo(ticker <-chan time.Time, procfunc gp.ProcessFunc) gp.Process {
	return gp.Go(goCallOnTicker(ticker, procfunc))
}
func TickerGo(ticker <-chan time.Time, procfunc gp.ProcessFunc) gp.Process {
	return gp.Go(goCallOnTicker(ticker, procfunc))
}
// TickerGo calls the given ProcessFunc every time the ticker fires.
// This is not rate limited, multiple calls could be in-flight at the same time.