Develop and track a metric to measure how long it takes for mutations to propagate to an index

Currently, there is no reliable metric to measure how long it takes for mutations in a bucket to propagate to secondary indexes.

There are customers today who would like to find ways to improve performance in this area (through cluster configuration, sizing, index configuration, etc.) and the first step to being able to do so is to be able to accurately measure and compare current performance as a baseline and then to be able to compare performance after changes have been made.