onEffectCleanup function
Implementation
void onEffectCleanup(void Function() callback, {bool failSilently = false}) {
final sub = alien.getActiveSub();
if (sub is _OrefEffect) {
sub.cleanup = callback;
} else if (!failSilently) {
warn(
'`onEffectCleanup()` was called when there was no active effect to assign the callback to.',
);
}
}