Script plugin for testing PocketMine async worker start closures.

AsyncPoolStartClosures.php

<?php

/**
 * @name AsyncPoolStartClosures
 * @main jacknoordhuis\test\AsyncPoolStartClosures
 * @version 1.0.0
 * @api 4.0.0
 * @author Jack Noordhuis
 */

declare(strict_types=1);

namespace jacknoordhuis\test {

	use GlobalLogger;
	use pocketmine\plugin\PluginBase;
	use pocketmine\scheduler\AsyncTask;

	class AsyncPoolStartClosures extends PluginBase {

		/** @var \Closure[] */
		protected $closures = [];

		protected function onEnable() : void {
			$this->closures = [
				static function() : void{
					GlobalLogger::get()->info("async worker start closure");
				}
			];

			// will log the message to any existing workers
			$this->getServer()->getAsyncPool()->addWorkerStartHook($closure = function(int $worker) : void {
				$task = new class($this->closures) extends AsyncTask {
					/** @var string */
					private $closures;

					/**
					 * @param \Closure[] $closures
					 */
					public function __construct(array $closures) {
						$this->closures = $closures;
					}

					public function onRun() : void {
						/** @var \Closure[] $closures */
						$closures = $this->closures;
						foreach($closures as $closure) {
							($closure)();
						}
					}
				};
				$this->getServer()->getAsyncPool()->submitTaskToWorker($task, $worker);
			});
			// the message will not be logged on any new workers
			$this->getServer()->getAsyncPool()->removeWorkerStartHook($closure);
		}
	}
}