Forget something as specific and hardcore as networking. I had a week to build a nodejs poc of a legacy spring/java app/service in Amazon that was doing a bunch of service to service auth with some Tibco messaging. I couldn't find any open implementations of Tibco clients (around 2013) and the frugality leadership principle meant getting an official spec would be almost impossible. I just needed a few details of the packet structure on a couple of requests. You can guess which tool saved the day for me here! Principle Eng at the time was surprised such a tool existed!