GoRoutine local storage using GoRoutine IDs

This package is heavily inspired by jtolds' gls package.

I made my own version of jtolds' package because Brad Fitzpatrick created a function to get the current GoRoutine ID. Am I a horrible person for using this function? Probably.

So far, the only thing I'm using it for is storing a unique identifier for a given HTTP request so I can track its progress through my code via logging. I felt this approach was easier and less messy than refactoring every function to take some kind of context or identifier.

Enjoy!