CoordinatedWorker can be zombied under throttling / multiple activites can run

[sclasen]

when we receive an error while attempting to heartbeat, we just continue here

https://github.com/sclasen/swfsm/blob/master/activity/coordinated_worker.go#L63

In the case where RecordActivityTaskHeartbeat is being constantly throttled, the worker will never get a heartbeat through, and never know that it was canceled.

In the meantime, since other APIs limits are not being hit, SWF will happliy time out the activity, and in most cases your decider will reschedule it.

That activity will also start getting throttled on heartbeats, and the deadly cycle will ensue.