PHP fibers and memory
Code loaded during Fiber execution is available afterwards. Running the following code in Drupal bootstrapped environment:
var_dump(class_exists('\Drupal\Core\Action\Plugin\Action\DeleteAction', FALSE));
$fiber = new Fiber(function() : void {
var_dump(class_exists('\Drupal\Core\Action\Plugin\Action\DeleteAction', TRUE));
});
$fiber->start();
var_dump(class_exists('\Drupal\Core\Action\Plugin\Action\DeleteAction', FALSE));
produces the following output:
bool(false)
bool(true)
bool(true)