Best practice for XDebug extension is to disable by default the coverage mode
as it slows too much the system, and enables it only when running unit tests.

This can be controlled by a specific php.ini file or by environment variable,
but not by passing -d value as it's an admin flag.

This is no-op when it's already set elsewhere or when another extension is used.

Even if the setting xdebug.mode is already set, PHPUnit only uses code coverage,
so it's not an issue to provide this value for phpunit run.

References:

• https://docs.phpunit.de/en/12.5/code-coverage.html
• https://xdebug.org/docs/code_coverage

Ref https://devcentral.nasqueron.org/T2316

With rKERUALD:

$ arc unit
   PASS  198ms   Keruald\OmniTools\Tests\HTTP\Requests\RequestTest