Raisin is a priority based coroutine manager with a few additional twists.
Its name in its prototyping stage was originally 'ryzen', the joke being
that it was a 'threadripper'. Obviously that name is a poor choice, so
something similar was decided upon. As is evident Raisin is designed for
lua's coroutines to allow for many freedoms, such as manual prioritization,
grouping, toggling, and a manual coroutine death termination amount.