null_write
static int null_write(BIO *h, const char *buf, int num);
.bwrite = null_write,
extern int null_write(void *, const char *, int);
ssize_t null_write(struct open_file *f, void *buf, size_t size, size_t *resid);
extern int null_write(void *, const char *, int);
null_write,