message: Fix Schedule fixed
diff: @@ -813,7 +813,8 @@ export function fixed(interval: number): Schedule<unknown, unknown, number> {
  ),
  ({ lastRun, startMillis }) => {
  const runningBehind = now > lastRun + interval
  - const boundary = (now - startMillis) % interval
  + const boundary =
  + interval === 0 ? interval : interval - ((now - startMillis) % interval)
  const sleepTime = boundary === 0 ? now : boundary
  const nextRun = runningBehind ? now : now + sleepTime
  