Skwasm uses WebAssembly.Function in order to export a callback to the skwasm module. This is unfortunate for several reasons:

• This creates a needless Wasm Function -> JS Function -> Wasm Function layering that is probably slow
• It creates a dependency on the type reflection proposal, which we'd like to avoid.
  The main reason I can't just export the callback directly is because we need access to the Wasm types in dart:_wasm in order to declare the proper signatures and also create a wasm function reference out of a dart function. I'll need to look into how we can give the flutter engine specifically access to the dart:_wasm library.