Improve Cleanup so it can cancel an action, making the actionOnException code far simpler
Add comments to the fields in Pool
Add isLeft_/isRight_ to the Base module
Move threadLimit into the mutable pool attributes
Add an increasePool function
Reorder the Pool module imports
Rewrite unsafeExtraThread not to depend on blockPool
Refactor the parallelism test in Basic
Add a test for unsafeExtraThread
Fix up the doc comments in Pool