tl;dr: Use Server-Timing HTTP header to help debug internal latencies. While this is useful for debugging, it does potentially expose how your services are connected to each other. Even so, the debugging benefits outway the privacy risk.

If you’re loading assets from a key-value store, you can expose how many milliseconds it took to retrieve the file by returning something like below.

// Response
Server-Timing: kv;dur=100, total;dur=200

For more information, please see Server-Timing on MDN