Task Timeout Fix

• Activity worker will release the semaphore when send_task_success raises a client error

Semaphore Activity Worker Control

Semaphore Worker Count Control (#9)

* address heartbeat timeout edge case

* revert back to using threadpools instead of process pools

* now properly tested

* remove debug code

* clarify docstring

* unnecessary magic num

* Tweak semaphore tests

Change ThreadPoolExecutor => ProcessPollExecutor

Change ThreadPoolExecutor => ProcessPoolExecutor (#8)

* change concurrent executor from thread to process

* increment version

Listener Threading

When instantiating the ActivityWorker you can now specify worker_count= to specify how many workers you would like to have running in parallel when using ActivityWorker.listen().

Default is worker_count=1.

Initial Release

The first release!

This initial release completely encapsulates all the work that goes into communicating with the StepFunctions API; all you need to do is provide a function that takes task input and returns task output!