# File lib/rack/test/utils.rb, line 44
      def multipart_body(params)
        multipart_requestify(params).map do |key, value|
          if value.respond_to?(:original_filename)
            ::File.open(value.path, "rb") do |f|
              f.set_encoding(Encoding::BINARY) if f.respond_to?(:set_encoding)

              "--\#{MULTIPART_BOUNDARY}\\r\nContent-Disposition: form-data; name=\"\#{key}\"; filename=\"\#{escape(value.original_filename)}\"\\r\nContent-Type: \#{value.content_type}\\r\nContent-Length: \#{::File.stat(value.path).size}\\r\n\\r\n\#{f.read}\\r\n"
            end
          else
"--\#{MULTIPART_BOUNDARY}\\r\nContent-Disposition: form-data; name=\"\#{key}\"\\r\n\\r\n\#{value}\\r\n"
          end
        end.join("")+"--#{MULTIPART_BOUNDARY}--\r"
      end