typedef size_t (*ReadFunc_t) (struct _KFile *fd, void *buf, size_t size);
typedef size_t (*WriteFunc_t) (struct _KFile *fd, const void *buf, size_t size);
typedef size_t (*ReadFunc_t) (struct _KFile *fd, void *buf, size_t size);
typedef size_t (*WriteFunc_t) (struct _KFile *fd, const void *buf, size_t size);