    # File lib/fog/rackspace/models/storage/files.rb, line 74
            def head(key, options = {})
              requires :directory
              data = service.head_object(directory.key, key)
              file_data = data.headers.merge({
                :key => key
              })
              new(file_data)
            rescue Fog::Storage::Rackspace::NotFound
              nil
            end