pocketmine\level\format\FullChunk::isPopulated PHP Method

    public function isPopulated();

 public function setChunk($chunkX, $chunkZ, FullChunk $chunk)
 {
     if (!$chunk instanceof Chunk) {
         throw new \Exception("Invalid Chunk class");
     }
     $chunk->setProvider($this);
     if ($chunk->isPopulated() === false) {
         $this->unloadChunk($chunkX, $chunkZ, false);
         $regionX = $regionZ = null;
         self::getRegionIndex($chunkX, $chunkZ, $regionX, $regionZ);
         $this->loadRegion($regionX, $regionZ);
         $region = $this->getRegion($regionX, $regionZ);
         $region->removeChunk($chunkX - $region->getX() * 32, $chunkZ - $region->getZ() * 32);
         $this->loadChunk($chunkX, $chunkZ);
     } else {
         $chunk->setX($chunkX);
         $chunk->setZ($chunkZ);
         $this->chunks[Level::chunkHash($chunkX, $chunkZ)] = $chunk;
         //$this->saveChunk($chunkX, $chunkZ);
     }
 }