pocketmine\level\format\leveldb\LevelDB::unloadChunk PHP Method

    public function unloadChunk($x, $z, $safe = true)
    {
        $chunk = isset($this->chunks[$index = Level::chunkHash($x, $z)]) ? $this->chunks[$index] : null;
        if ($chunk instanceof FullChunk and $chunk->unload(false, $safe)) {
            unset($this->chunks[$index]);
            return true;
        }
        return false;
    }