# File lib/twitter/rest/request/multipart_with_file.rb, line 14
        def call(request)
          request.body.each do |key, value|
            next unless value.respond_to?(:to_io)
            request.body[key] = Faraday::UploadIO.new(value, mime_type(value.path), value.path)
          end if request.body.is_a?(::Hash)
          @app.call(request)
        end