About useEffect

Inside 'useEffect'

void useEffect(Dispose? Function() effect, [List<Object?>? keys]) {
  use(_EffectHook(effect, keys));
}

Function() is first argument, list of keys is second argument

the comment written above the useEffect function is

/// [useEffect] is called synchronously on every `build`, unless
/// [keys] is specified. In which case [useEffect] is called again only if
/// any value inside [keys] as changed.