The original implementation returned `nil` if there weren't any timers:

https://github.com/celluloid/timers/blob/master/lib/timers.rb#L52

And 0 if it were ready to fire now:

https://github.com/celluloid/timers/blob/master/lib/timers.rb#L54

I don't think there's any meaningful reason to move away from this API. You can change the sleep line in #wait to:

```ruby
sleep i if i > 0
```

and it accomplishes the same thing, without changing the API.