code: public function run()
      {
          $signalHandler = $this->getSignalHandler();
          $signalHandler->registerHandler(SIGTERM, function () {
              $this->shouldShutdown = true;
          });
  
          $this->sharedMemory[self::STARTED_MARKER] = true;
  
          /** @var callable $callable */
          $callable = $this->callable;
          $callable($this);
      }
docs: Execute callable.