Why using a AsyncJob instead of a Future directly?

[dgkim5360]

Why using a AsyncJob instead of a Future directly?

[dgkim5360]

I agree with your point. It seems that I had no brake for enough consideration, a half year ago.

In my current opinion, there's no need to implement a custom Future-like class here. And it would be the best to use a native concurrent.Futuredirectly.

[dgkim5360]

I add a commit which changes the following.

1. AsyncLoop.submit returns Future object directly.
2. AsyncJob is replaced with the simpler object PendingJob to be stored in the pending queue AsyncLoop.pending.

What do you think? Any feedback would be appreciated.
(If you want to review before the commit, I will do PR next time.)