class ActiveStorage::Service::GCSService

def compose(source_keys, destination_key, filename: nil, content_type: nil, disposition: nil, custom_metadata: {})
  bucket.compose(source_keys, destination_key).update do |file|
    file.content_type = content_type
    file.content_disposition = content_disposition_with(type: disposition, filename: filename) if disposition && filename
    file.metadata = custom_metadata
  end
end