Method is_open

src/fl/system/file_system.cpp.hpp:40–40

    ~NullFileHandle() FL_NOEXCEPT override {}

    bool is_open() const override { return false; }
    fl::size_t size() const override { return 0; }
    fl::size_t read(char *dst, fl::size_t bytesToRead) override {
        FASTLED_UNUSED(dst);