sendfromto
len = sendfromto(s, r->sendbuf->v, r->sendbuf->l,
len = sendfromto(s, sbuf->v, sbuf->l,
len = sendfromto(s, keepalive_packet, sizeof (keepalive_packet),
extern int sendfromto(int, const void *, size_t,
(void) sendfromto(s, buffer, (size_t)i, 0,
(void) sendfromto(s, text, sizeof(text), 0, lsa, lsize, rsa, rsize);
(void)sendfromto(s, &result, sizeof(result), 0, lsa, lsize, rsa, rsize);
(void) sendfromto(s, buffer, (size_t)len, 0, lsa, lsize, rsa, rsize);
static ssize_t sendfromto(int, const void *, size_t, int,