Function types being converted to dynamic types

Hxcpp transforms function types into dynamics (shown [here](https://imgur.com/a/NxXJ7iM)). Surely it should be converted into a C++ callback in the traditional sense or Callable?

Using [HxScout ](https://hxscout.com/) showed a large object footprint when using function types for callbacks, i.e. `var func : Float -> Void;` and then calling `func(3.0)`. A 'Float' object was created each frame which then needed to be garbage collected. This incurs a big cost at runtime because any time a callback is required, the garbage collector is clearing up potentially thousands of objects that have been seemingly generated for no reason.