#define DELEGATE(OBJ, METHOD, METHOD_AS)                                       \
  template <typename... Args> decltype(auto) METHOD_AS(Args &&...args) {       \
    return OBJ->METHOD(std::forward<Args>(args)...);                           \
  }

#define DEFINE_SETTER(METHOD, PROPERTY)                                        \
  template <typename Arg> void METHOD(Arg val) { PROPERTY = val; }

#define DEFINE_GETTER(METHOD, EXPR)                                            \
  template <typename Arg> decltype(auto) METHOD() { return EXPR; }