Method allocate

src/vector/vstackallocator.h:122–125

    template <class _Up> struct rebind {using other = stack_alloc<_Up, N, alignment>;};

    T* allocate(std::size_t n)
    {
        return reinterpret_cast<T*>(a_.template allocate<alignof(T)>(n*sizeof(T)));
    }
    void deallocate(T* p, std::size_t n) noexcept
    {
        a_.deallocate(reinterpret_cast<char*>(p), n*sizeof(T));