attach method
Registers this callback and returns its native function pointer.
Adds this to registry if not already present, then returns
nativeFunction. Pass the result directly to the native attach API:
rl.Audio.AttachAudioMixedProcessor(callback.attach());
Implementation
Pointer<NativeFunction<C>> attach() {
if (!registry.contains(this)) registry.add(this);
return nativeFunction;
}