CpuPool does not schedule futures fairly for execution

[carllerche]

CpuPool will immediately re-poll futures that were notified during poll. This means that futures that are under load (handling a queue) are unable to yield and will starve other futures.

https://github.com/alexcrichton/futures-rs/blob/master/src/task_impl/std/mod.rs#L452

[aturon]

Thanks for the report, I'll try to fix this soon.

[aturon]

Note: a similar issue applies to LocalPool::run_until.