public function createExecution($concurrent = true)
    {
        $execution = new static(UUID::createRandom(), $this->engine, $this->model, $this);
        $execution->setNode($this->node);
        
        if ($concurrent) {
            $execution->state |= self::STATE_CONCURRENT;
        }
        
        $this->engine->registerExecution($execution);
        
        $this->engine->debug(sprintf('Created %s{execution} from {parent}', $concurrent ? 'concurrent ' : ''), [
            'execution' => (string) $execution,
            'parent' => (string) $this
        ]);
        
        return $execution;
    }