How to debug a scrapy Request object?

requestobj= FormRequest.from_response(response, formxpath =form_xpath,callback=self.parse1)

I need to check formdata of requestobj .But I didn't find any documentation for debugging Request object
try sending request to:
http://httpbin.org/
or 
http://echo.opera.com/
you will get a response with information your request
scrapy debug Request object