Update c->sent in ngx_ssl_send_chain() even if SSL buffer is not used.

src/event/ngx_event_openssl.c

@@ -995,6 +995,7 @@ ngx_ssl_send_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
             }
 
             in->buf->pos += n;
+            c->sent += n;
 
             if (in->buf->pos == in->buf->last) {
                 in = in->next;