Allows working dimensions to exist in PMMP

dimensions.php

<?php
/**
 * @name Dimensions
 * @main jasonwynn10\Dimensions\Main
 * @version 0.1.0
 * @api 3.0.0-ALPHA9
 * @description A plugin script which allows working dimensions to exist in PMMP's PocketMine-MP
 * @author jasonwynn10
 */
namespace jasonwynn10\Dimensions {

	use pocketmine\block\Block;
	use pocketmine\event\server\DataPacketReceiveEvent;
        use pocketmine\event\Listener;
	use pocketmine\network\mcpe\protocol\ChangeDimensionPacket;
	use pocketmine\network\mcpe\protocol\PlayerActionPacket;
	use pocketmine\network\mcpe\protocol\PlayStatusPacket;
	use pocketmine\network\mcpe\protocol\types\DimensionIds;
	use pocketmine\Player;
	use pocketmine\plugin\Plugin;
	use pocketmine\plugin\PluginBase;
	use pocketmine\scheduler\PluginTask;

	class Main extends PluginBase implements Listener {
		public function onEnable() {
			$this->getServer()->getPluginManager()->registerEvents($this, $this);
		}
		public function onPacket(DataPacketReceiveEvent $ev) {
			$packet = $ev->getPacket();
			if($packet->pid() === PlayerActionPacket::NETWORK_ID) {
				/** @var PlayerActionPacket $packet */
				if($packet->action === PlayerActionPacket::ACTION_DIMENSION_CHANGE_REQUEST) {
					$blockId = $ev->getPlayer()->getLevel()->getBlock($ev->getPlayer()->asVector3())->getId();
					if($blockId === Block::PORTAL) {
						if(!isset($ev->getPlayer()->dimension) or $ev->getPlayer()->dimension !== DimensionIds::NETHER) {
							$ev->getPlayer()->dimension = DimensionIds::NETHER;
							$pk = new ChangeDimensionPacket();
							$pk->dimension = DimensionIds::NETHER;
							$pk->position = $ev->getPlayer()->asPosition();
							$ev->getPlayer()->dataPacket($pk);
							//TODO: other players should not be able to see entities across dimensions
							$this->getServer()->getScheduler()->scheduleDelayedTask(new class($this, $ev->getPlayer()->getName()) extends PluginTask {
								public function __construct(Plugin $owner, string $player) {
									parent::__construct($owner);
									$this->player = $player;
								}
								public function onRun(int $currentTick) {
									/** @var Player|null $player */
									$player = $this->getOwner()->getServer()->getplayer($this->player);
									$pk = new PlayStatusPacket();
									$pk->status = PlayStatusPacket::PLAYER_SPAWN;
									$pk->protocol = 130;
									$player->getPlayer()->dataPacket($pk);
								}
							}, 10); // send after .5 seconds
						}else{
							$ev->getPlayer()->dimension = 0;
							$pk = new ChangeDimensionPacket();
							$pk->dimension = 0;
							$pk->position = $ev->getPlayer()->asPosition();
							$ev->getPlayer()->dataPacket($pk);
							//TODO: other players should not be able to see entities across dimensions
							$this->getServer()->getScheduler()->scheduleDelayedTask(new class($this, $ev->getPlayer()->getName()) extends PluginTask {
								public function __construct(Plugin $owner, string $player) {
									parent::__construct($owner);
									$this->player = $player;
								}
								public function onRun(int $currentTick) {
									/** @var Player|null $player */
									$player = $this->getOwner()->getServer()->getplayer($this->player);
									$pk = new PlayStatusPacket();
									$pk->status = PlayStatusPacket::PLAYER_SPAWN;
									$pk->protocol = 130;
									$player->getPlayer()->dataPacket($pk);
								}
							}, 10); // send after .5 seconds
						}
					}
				}
			}
		}
	}
}

how?

Join a nether portal

It's supposed to match vanilla, but the code is made for API 3 alpha9