Make use of Server-Timing headers to monitor performances
HTTP Requests can send some monitoring informations about the server with the Server-Timing
header:
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Server-Timing
I think we could use that when it's required to monitor the server response time (some timings but also the number of SQL queries, etc). Those data could be linked to a transaction, a context manager could be used to monitor some specific part of the code.