How to benchmark your ruby gem

We made a huge push to make Flipper more performant the past week or so (results at the end). It wasn't that hard, but I realized I haven't seen any articles like the one I'm about to write. Most of them are "here are all the tools" and/or "a single example" of how to use that tool.What I felt they were missing was a general approach of how to take something and make it faster. So here goes nothing...