src/Gaufrette/Core/Operator/LastModificationOperator.php
public function save(File $file, Adapter $adapter)
    {
        $datetime = $file->getLastModification();

        if (null !== $datetime) {
            $adapter->writeLastModification($file->getName(), $datetime->format('U'));
        }

        return $this;
    }
public function save(File $file, Adapter $adapter)
    {
        $datetime = $file->getLastModification();

        if (null !== $datetime) {
            $adapter->writeLastModification($file->getName(), $datetime->format('U'));
        }

        return $this;
    }
{@inheritdoc}