def save(filename, path, params={})
      payload = get! path, nil, params
      File.write filename, payload.response.body
    end
def save(filename, path, params={})
      payload = get! path, nil, params
      File.write filename, payload.response.body
    end
Save the response body to a file

 === Example

   client = Client.new
   client.save 'out.json', 'some/to/resource', param: value