Allow for concurrency when calling CloudWatch API

![getinsertpic.com](http://media4.giphy.com/media/vLCExVUyRj20/200.gif)

## Problem

The CloudWatch API is potentially a blocking call (even more so since we're having to lookup the last set value for the specified metric - that's if the user hasn't provided a specific value to be set - and then decide whether the value should be incremented or reset to zero, depending on if a value had been set within the last hour).

## Solution

Thread it.