public function sendData($player, array $data = null)
{
$pk = new SetEntityDataPacket();
$pk->eid = $player === $this ? 0 : $this->getId();
$pk->metadata = $data === null ? $this->dataProperties : $data;
if (!is_array($player)) {
$player->dataPacket($pk);
} else {
Server::broadcastPacket($player, $pk);
}
}