code: function _Http_multipart(parts) {
      for (
        var formData = new FormData();
        parts.b;
        parts = parts.b // WHILE_CONS
      ) {
        var part = parts.a;
        formData.append(part.a, part.b);
      }
  
      return elm$http$Http$Internal$FormDataBody(formData);
    }
docs: BODY