88 class OnceCallback<R(Args...)> : public internal::CallbackBase {
95   constexpr OnceCallback() = default;
96   OnceCallback(std::nullptr_t) = delete;
98   explicit OnceCallback(internal::BindStateBase* bind_state)  in OnceCallback()  function
101   OnceCallback(const OnceCallback&) = delete;
102   OnceCallback& operator=(const OnceCallback&) = delete;
104   OnceCallback(OnceCallback&&) noexcept = default;
105   OnceCallback& operator=(OnceCallback&&) noexcept = default;
107   OnceCallback(RepeatingCallback<RunType> other)  in OnceCallback()  function
110   OnceCallback& operator=(RepeatingCallback<RunType> other) {
127     OnceCallback cb = std::move(*this);  in Run()
144   OnceCallback<ThenR(Args...)> Then(OnceCallback<ThenR(ThenArgs...)> then) && {  in Then()
148             OnceCallback, OnceCallback<ThenR(ThenArgs...)>>::CreateTrampoline(),  in Then()
156   OnceCallback<ThenR(Args...)> Then(  in Then()
161             OnceCallback,  in Then()