Merge cherrypicks of [9736358, 9736296, 9735406, 9736235, 9736059, 9736060,...

    template<size_t N>

    static size_t align(void*& buffer) {

        return align<N>( const_cast<void const*&>(buffer) );

        static_assert(!(N & (N - 1)), "Can only align to a power of 2.");

        void* b = buffer;

        buffer = reinterpret_cast<void*>((uintptr_t(buffer) + (N-1)) & ~(N-1));

        size_t delta = size_t(uintptr_t(buffer) - uintptr_t(b));

        memset(b, 0, delta);

        return delta;

    }

    static void advance(void*& buffer, size_t& size, size_t offset) {