How to represent callbacks in WASI?

I'm looking to create a Signal engine like how SolidJS works, with a WASI interface. The way Solid handles dependency tracking is the provided callback is called once during declaration and the getters add the callback as a dependency of their signals, using a global variable to store the callback for the getters to reference. To implement this kind of functionality, I need to implement callbacks. In other words, the engine will provide a createEffect() function that a wasm component will use by passing in the callback to invoke whenever the signals update. Since WASI doesn't seem to support functions as parameters directly, what's the best way to do this?

No source file, test, or entry point is identified. Start by reading the WASI interface documentation and the WebAssembly function-parameter model, then compare them with the callback and dependency-tracking requirements described here. Done means a maintainer-approved design for representing and invoking callbacks.