1. Moved callsite to `createRenderState`. This differs from feedback, though I believe is a better location, seeing as the method is final and will apply modifiers if users call the method.
2. Some classes have been renamed to better reflect behavior
3. Use ContextKey instead of custom class
4. Retain each modifier separately so that subclasses may be considered
5. Use lazily evaluated map for storing all modifiers that apply to a given renderer