I think I'm changing my mind about the cost benefit tradeoff of this at the moment -- we'd need to burn a fair bit of memory for *all* users maintaining the information to be logged, and it would only be useful in a very small number of reports.

Let's see if the proposed to chrome://net-internals gets us enough information without adding that overhead.  We should revisit this if it looks like it will help with long-term debugging though.