Method setMinFramesAhead

tests/VideoCacheThread.cpp:42–42

    void    setLastCachedIndex(int64_t v) { last_cached_index.store(v); }
    void    setPlayhead(int64_t v) { requested_display_frame.store(v); }
    void    setMinFramesAhead(int64_t v) { min_frames_ahead.store(v); }
    void    setLastDir(int d) { last_dir.store(d); }
    void    forceUserSeekFlag() { userSeeked.store(true); }
    bool    isScrubbing() const { return scrub_active.load(); }