EventListener/TimestampableSubscriber.php
public function loadClassMetadata(LoadClassMetadataEventArgs $eventArgs)
    {
        $this->classMetadata = $eventArgs->getClassMetadata();
        $reflectionClass     = $this->classMetadata->getReflectionClass();

        if (null === $reflectionClass) {
            return;
        }

        if ($this->hasMethod($reflectionClass, 'updateTimestamps')) {
            $this->addLifecycleCallbacks();
            $this->mapFields();
        }
    }
public function loadClassMetadata(LoadClassMetadataEventArgs $eventArgs)
    {
        $this->classMetadata = $eventArgs->getClassMetadata();
        $reflectionClass     = $this->classMetadata->getReflectionClass();

        if (null === $reflectionClass) {
            return;
        }

        if ($this->hasMethod($reflectionClass, 'updateTimestamps')) {
            $this->addLifecycleCallbacks();
            $this->mapFields();
        }
    }
Event triggered during metadata loading

@param LoadClassMetadataEventArgs $eventArgs