ssl_read_internal
ret = ssl_read_internal(ssl, buf, size, readbytes);
ret = ssl_read_internal(s, buf, (size_t)num, &readbytes);
int ret = ssl_read_internal(s, buf, num, readbytes);
__owur int ssl_read_internal(SSL *s, void *buf, size_t num, size_t *readbytes);