Observe ACK queue peaks before immediate send

tests/test_etcp_multipath.c

@@ -305,6 +305,7 @@ static void observe_packet(struct ETCP_DGRAM* pkt, struct ETCP_LINK* link, int s
     int side = link->etcp->instance == ep[0].inst ? 0 : 1, path = -1;
     for (unsigned p = 0; p < path_count; p++)
         if (ss_get_port(&link->remote_addr) == dummynet_get_listen_port(channels[p])) path = p;
+    if (path >= 0 && !sending) diagnostic_for(link);
     if (path >= 0) for (unsigned offset = 0; offset < pkt->data_len;) {
         const uint8_t* data = pkt->data + offset;
         unsigned remaining = pkt->data_len - offset, len;
@@ -418,7 +419,11 @@ int __wrap_queue_data_put_with_index(struct ll_queue* q, struct ll_entry* entry)
             }
         }
     }
-    return __real_queue_data_put_with_index(q, entry);
+    int result = __real_queue_data_put_with_index(q, entry);
+    if (!result && diagnostic_active) for (unsigned side = 0; side < 2; side++)
+        for (struct ETCP_LINK* l = ep[side].conn->links; l; l = l->next)
+            if (q == l->ack_q) diagnostic_for(l); // ACK-пик виден до немедленной отправки/извлечения из очереди.
+    return result;
 }
 
 struct ETCP_LINK* __real_etcp_loadbalancer_select_link(struct ETCP_CONN*, uint32_t, const struct INFLIGHT_PACKET*);