Mini WordPress core server performance test suite

Purpose

This quick "mini test suite" allows you to easily collect server-side performance metrics for WordPress core development. It does so by utilizing the Server-Timing header.

Usage

1. Paste the code from main.php into pretty much anywhere in WordPress core, e.g. into wp-includes/default-filters.php.
2. Use code like the one in example.com around any code or a specific function that you want to record metrics for.