fuse_reply_buf
DEF(fuse_reply_buf);
int fuse_reply_buf(fuse_req_t, const char *, off_t);
fuse_reply_buf(req, fd->buf + offset, size);
fuse_reply_buf(req, fd->buf, fd->len > size ? size :
fuse_reply_buf(req, buf, err);
PROTO(fuse_reply_buf);
fuse_reply_buf(req, (const char *)&out, sizeof(out));