Flux is a monoid which counts the number of times an element changes (according to its Eq instance) This is useful for gaining associativity (and its associated performance improvements) for tasks where you'd otherwise use group or groupBy

It also allows usage of change-detection semantics in situations where a Monoid is required; e.g. in a FingerTree

> getFlux $ foldMap flux ["a", "b", "b", "a"]
2
> getFlux $ foldMap flux ["a", "b", "b", "a", "c", "c", "c"]
3