def download(key, &block)
      source = cloudinary_url_for_key(key)

      if block_given?
        instrument :streaming_download, key: key do
          stream_download(source, &block)
        end
      else
        instrument :download, key: key do
          Cloudinary::Downloader.download(source)
        end
      end
    end
def download(key, &block)
      source = cloudinary_url_for_key(key)

      if block_given?
        instrument :streaming_download, key: key do
          stream_download(source, &block)
        end
      else
        instrument :download, key: key do
          Cloudinary::Downloader.download(source)
        end
      end
    end
Return the content of the file at the +key+.