The 8 ms of autoloading that was a misconfigured classmap

Eight milliseconds of every request spent resolving class paths, on a deploy that was running the wrong Composer command.

# the deploy ran
composer install --no-dev

# which does not optimise. what it should run
composer install --no-dev --classmap-authoritative

# 412 stat() calls per request → 0
# 8.1ms → 0.2ms

# and the check, in the health endpoint
'autoload' => class_exists('Composer\Autoload\ClassLoader')
    && ! empty((new ReflectionClass(ClassLoader::class))
        ->getProperty('classMapAuthoritative')),

Eight milliseconds spread across every request is the kind of cost that never appears in a profile as a line worth looking at, because it is distributed rather than concentrated. Asserting the autoloader mode in the health endpoint is the part worth copying — a deploy script change in 2021 had silently removed the flag and nothing anywhere would have said so.