thunk_pwrite
ret = thunk_pwrite(sc->sc_fd, bp->b_data, bp->b_bcount, offset);
len = thunk_pwrite(sc->sc_fd, data, blkcnt, blkno * ld->sc_secsize);
ssize_t thunk_pwrite(int, const void *, size_t, off_t);
wlen = thunk_pwrite(mem_fh, &dummy, 1, file_len - 1);
wlen = thunk_pwrite(mem_fh, block, PAGE_SIZE, pg);
written = thunk_pwrite(mem_fh, (void *) kmem_k_start, kmem_k_length,