Function scan_with_callbacks 

pub fn scan_with_callbacks<ShouldStop, OnProgress, OnRecord>(
    opts: &ScanOptions,
    should_stop: &mut ShouldStop,
    on_progress: &mut OnProgress,
    on_record: &mut OnRecord,
) -> Result<(u64, u64), ScanError>
where
    ShouldStop: FnMut() -> bool,
    OnProgress: FnMut(ScanProgress),
    OnRecord: FnMut(FileRecord) -> Result<(), ScanError>,