int (*fill_io_u_off)(struct thread_data *, struct io_u *);
int (*fill_io_u_size)(struct thread_data *, struct io_u *);
struct fio_file *(*get_next_file)(struct thread_data *);
int (*fill_io_u_off)(struct thread_data *, struct io_u *);
int (*fill_io_u_size)(struct thread_data *, struct io_u *);
struct fio_file *(*get_next_file)(struct thread_data *);