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

    public function setGenerated($value = 1);

 public function generateChunk($chunkX, $chunkZ)
 {
     if ($this->emptyChunk !== null) {
         //Use the cached empty chunk instead of generating a new one
         $this->chunk = clone $this->emptyChunk;
     } else {
         $this->chunk = clone $this->level->getChunk($chunkX, $chunkZ);
         $this->chunk->setGenerated();
         $c = Biome::getBiome(1)->getColor();
         $R = $c >> 16;
         $G = $c >> 8 & 0xff;
         $B = $c & 0xff;
         for ($Z = 0; $Z < 16; ++$Z) {
             for ($X = 0; $X < 16; ++$X) {
                 $this->chunk->setBiomeId($X, $Z, 1);
                 $this->chunk->setBiomeColor($X, $Z, $R, $G, $B);
                 for ($y = 0; $y < 128; ++$y) {
                     $this->chunk->setBlockId($X, $y, $Z, Block::AIR);
                 }
             }
         }
         $spawn = $this->getSpawn();
         if ($spawn->getX() >> 4 === $chunkX and $spawn->getZ() >> 4 === $chunkZ) {
             $this->chunk->setBlockId(0, 64, 0, Block::GRASS);
         } else {
             $this->emptyChunk = $this->chunk;
         }
     }
     $chunk = clone $this->chunk;
     $chunk->setX($chunkX);
     $chunk->setZ($chunkZ);
     $this->level->setChunk($chunkX, $chunkZ, $chunk);
 }