Struct VMNativeCallFunction 

pub struct VMNativeCallFunction(/* private fields */);

A function pointer that exposes the native calling convention.

Different Wasm function types end up mapping to different Rust function types, so this isn’t simply a type alias the way that VMArrayCallFunction is.

This is the default calling convention for the target (e.g. System-V or fast-call) except multiple return values are handled by returning the first return value in a register and everything else through a return-pointer.