// Fsync on HFS/OSX flushes the data on to the physical drive but the drive // may not write it to the persistent media for quite sometime and it may be // written in out-of-order sequence. Using F_FULLFSYNC ensures that the // physical drive's buffer will also get flushed to the media. func Fsync(f *os.File) error { … } // Fdatasync on darwin platform invokes fcntl(F_FULLFSYNC) for actual persistence // on physical drive media. func Fdatasync(f *os.File) error { … }