I am writing code that will let Arduino sent http posts to a IOT cloud service (thethings.io). The Arduino (Adafruit Trinket Pro 3v) uses AT commands to control a cellular module (Adafruit FONA 3G). The AT commands specify http headers and body of the http post. The server I am calling is returning 400 bad request, but it does not echo back to me the actual HTTP request so that I can see what is malformed. What ways are there to view the raw output of an HTTP request? Sites/services/tools?