Method set_then

src/fl/task/task.cpp.hpp:124–127

        , mLastRunTime((numeric_limits<u32>::max)()) {}

    void set_then(function<void()> on_then) override {
        mThenCallback = fl::move(on_then);
        mHasThen = true;
    }

    void set_catch(function<void(const Error&)> on_catch) override {
        mCatchCallback = fl::move(on_catch);