Possible fix for crashing server not stopping

src/pocketmine/Server.php

@@ -132,6 +132,8 @@ class Server{
 	/** @var bool */
 	private $isRunning = true;
 
+	private $hasStopped = false;
+
 	/** @var PluginManager */
 	private $pluginManager = null;
 
@@ -1852,6 +1854,13 @@ class Server{
 	}
 
 	public function forceShutdown(){
+		if($this->hasStopped){
+			return;
+		}
+
+		try{
+			$this->hasStopped = true;
+
 			$this->shutdown();
 			if($this->rcon instanceof RCON){
 				$this->rcon->stop();
@@ -1877,15 +1886,21 @@ class Server{
 			}
 
 			HandlerList::unregisterAll();
+
 			$this->scheduler->cancelAllTasks();
 			$this->scheduler->mainThreadHeartbeat(PHP_INT_MAX);
 
 			$this->properties->save();
 
 			$this->console->kill();
+
 			foreach($this->interfaces as $interface){
 				$interface->shutdown();
 			}
+		}catch (\Exception $e){
+			$this->logger->emergency("Crashed while crashing, killing process");
+			@kill(getmypid());
+		}
 	}
 
 	/**

src/pocketmine/scheduler/ServerScheduler.php

@@ -144,7 +144,7 @@ class ServerScheduler{
 		}
 		$this->tasks = [];
 		$this->asyncTaskStorage = [];
-		$this->asyncPool->shutdown();
+		//$this->asyncPool->shutdown();
 		$this->asyncTasks = 0;
 		$this->queue = new ReversePriorityQueue();
 		$this->asyncPool = new \Pool(self::$WORKERS, AsyncWorker::class);