an example of SyncActorPropertyPacket for server -> resourcepack communication

propertysynctest.php

<?php

use pocketmine\entity\Entity;
use pocketmine\event\EventPriority;
use pocketmine\event\player\PlayerChatEvent;
use pocketmine\event\player\PlayerItemHeldEvent;
use pocketmine\event\server\DataPacketSendEvent;
use pocketmine\nbt\NBT;
use pocketmine\nbt\tag\CompoundTag;
use pocketmine\nbt\tag\ListTag;
use pocketmine\nbt\tag\StringTag;
use pocketmine\network\mcpe\protocol\AddActorPacket;
use pocketmine\network\mcpe\protocol\ItemRegistryPacket;
use pocketmine\network\mcpe\protocol\SetActorDataPacket;
use pocketmine\network\mcpe\protocol\SyncActorPropertyPacket;
use pocketmine\network\mcpe\protocol\types\CacheableNbt;
use pocketmine\network\mcpe\protocol\types\entity\PropertySyncData;
use pocketmine\plugin\PluginBase;

/**
 * @main propertysynctest
 * @api 5.0.0
 */
class propertysynctest extends PluginBase{

	protected function onEnable() : void{
		$this->getServer()->getPluginManager()->registerEvent(DataPacketSendEvent::class, function(DataPacketSendEvent $event) : void{
			foreach($event->getPackets() as $packet){
				if($packet instanceof ItemRegistryPacket){
					foreach($event->getTargets() as $target){
						$target->sendDataPacket(SyncActorPropertyPacket::create(
							new CacheableNbt(
								CompoundTag::create()
									->setTag(
										"properties",
										new ListTag(
											[
												CompoundTag::create()
													->setTag("enum", new ListTag([
														new StringTag("unrolled"),
														new StringTag("rolled_up"),
														new StringTag("rolled_up_peeking"),
														new StringTag("rolled_up_relaxing"),
														new StringTag("rolled_up_unrolling")
													], NBT::TAG_String))
													->setString("name", "minecraft:armadillo_state")
													->setInt("type", 3)
											],
											NBT::TAG_Compound
										)
									)
									->setString("type", "minecraft:armadillo")
							)
						), true);
					}
				}
			}
		}, EventPriority::LOWEST, $this);

		$id = null;
		$this->getServer()->getPluginManager()->registerEvent(PlayerChatEvent::class, function(PlayerChatEvent $event) use (&$id) : void{
			if($event->getMessage() === "a"){
				$player = $event->getPlayer();
				$pos = $player->getPosition();
				$player->getNetworkSession()->sendDataPacket(AddActorPacket::create(
					$id = Entity::nextRuntimeId(),
					$id,
					"minecraft:armadillo",
					$pos->asVector3(),
					null,
					0.0,
					0.0,
					0.0,
					0.0,
					[],
					[],
					new PropertySyncData([0 => 0], []),
					[]
				));
			}
		}, EventPriority::NORMAL, $this);
		$this->getServer()->getPluginManager()->registerEvent(PlayerItemHeldEvent::class, function(PlayerItemHeldEvent $event) use (&$id) : void{
			if($id === null){
				return;
			}
			$player = $event->getPlayer();
			$session = $player->getNetworkSession();
			$slot = $event->getSlot();
			if($slot >= 0 && $slot <= 4){
				var_dump("PlayerItemHeldEvent slot: $slot, id: $id");
				$session->sendDataPacket(SetActorDataPacket::create(
					$id,
					[],
					new PropertySyncData(
						[0 => $slot],
						[]
					),
					0
				));
			}
		}, EventPriority::NORMAL, $this);
	}
}