code: function (name, value, options) {
          $this._multipart.push({
            name: name,
            value: value,
            options: options,
            attachment: options.attachment || false
          })
        }
docs: Attaches field to the multipart-form request, with no pre-processing.
  
  @param  {String} name
  @param  {String|Object} path
  @param  {Object} options
  @return {Object}