This is part of the #285 meta.

Description of the need

Respective issue:

Providing server timing would help developers estimate site performance. The corresponding W3C specification is currently in "Working Draft" status and its already supported by Google Chrome and Firefox.

This specification enables a server to communicate performance metrics about the request-response cycle to the user agent. It also standardizes a JavaScript interface to enable applications to collect, process, and act on these metrics to optimize application delivery.

Symfony adopted it in

Proposed solution

Add Server-Timing header with relevant timing information.

GitHub Issue #: