During a metric report, sinks must build a unique name for each metric based on the base name, metadata and a units string This currently has to be done on each report for each metric. Since this information is immutable for each metric, it is extra processing that is redundant. While reports are not that often, if 100s of metrics are reported, the time to regenerate metric report names for each metric on each report will add up. Adding a unique ID to each metric allows sinks to build the report names, and other per metric values, a single time and reuse them.