public function downloadProxy($hash)
 {
     return $this->factory->createProxy(ChunkInterface::class, function () use($hash) {
         return $this->download($hash);
     });
 }
 public function fetchProxy($hash, $className)
 {
     return $this->factory->createProxy($className, function () use($hash, $className) {
         return $this->fetch($hash, $className);
     });
 }