Send+Sync bound expectations on some types

[ten3roberts]

Worley noise (and some other functions) contain custom Rc<Fn> distance functions.

Usage of Rc makes these types non-Send, which makes it difficult to use in many ECS implementations

Would it be possible to change the type to Arc or possibly introduce a generic with a default value to get around these limitations?

error[E0277]: `Rc<(dyn for<'a, 'b> std::ops::Fn(&'a [f64], &'b [f64]) -> f64 + 'static)>` cannot be shared between threads safely
   --> shared/src/entities/enemy_controller.rs:150:17
    |
150 |     idle_state: IdleState,
    |                 ^^^^^^^^^ `Rc<(dyn for<'a, 'b> std::ops::Fn(&'a [f64], &'b [f64]) -> f64 + 'static)>` cannot be shared between threads safely
    |
    = help: within `IdleState`, the trait `Sync` is not implemented for `Rc<(dyn for<'a, 'b> std::ops::Fn(&'a [f64], &'b [f64]) -> f64 + 'static)>`, which is required by `IdleState: ComponentValue`
note: required because it appears within the type `Worley`
   --> /home/freja/.cargo/registry/src/index.crates.io-6f17d22bba15001f/noise-0.9.0/src/noise_fns/generators/worley.rs:11:12
    |
11  | pub struct Worley {

From looking at the code, a non-Send distance function is not required, as the provided distance functions are purely "math" and thus could be send.

Thanks