Default AWS S3 metadata?

[broncha]

Hi,
We have a use case where liip imagine stores the output of filters to S3 using gaufrette file system.
Now we need to add default 'CacheControl' metadata to all files uploaded to this filesystem, and I cant find a way to do that.

Wherever we upload files ourselves, we are doing

$adapter->setMetadata($filename, [
    'CacheControl' => 'max-age=31556952'
]);

But I can't find anything that allows us to define default metadata for AwsS3 Adapter from this bundle.
AwsS3 Adapter itself accepts options but the configuration in this bundle only few params