pocketmine\level\format\LevelProvider::setSpawn PHP Method

    public function setSpawn(Vector3 $pos);

 /**
  * Sets the level spawn location
  *
  * @param Vector3 $pos
  */
 public function setSpawnLocation(Vector3 $pos)
 {
     $previousSpawn = $this->getSpawnLocation();
     $this->provider->setSpawn($pos);
     $this->server->getPluginManager()->callEvent(new SpawnChangeEvent($this, $previousSpawn));
 }