Method SizedLazyFileNode

src/vfs/vfs.h:177–183

public:
    using SizeFn = std::function<u64()>;
    SizedLazyFileNode(std::string name, SizeFn size_fn, FileProducer p,
                      FileCost cost = {})
        : Node(std::move(name), Kind::File)
        , size_fn_(std::move(size_fn))
        , producer_(std::move(p)) {
        cost_ = cost;
    }
    u64 size() override;
    // size() is already cheap here (uses size_fn_), so the default
    // size_hint()==size() is fine — no override needed.