First off: We are open to solving this problem in one of many ways!
We are trying to capture the number of users who give up on the page before it fully loads (and before GA & other metrics platforms fire). We can currently do this by counting the number of queries that reach our CDN but are not fulfilled by our webserve (via analysis on Google Analytics). When we move behind ARC's CDN, we'd like to track a similar metric. Thank you!
As discussed with the Delivery team and Akamai, this is not possible.