feat(desktop): expose delayed frame completion and QUIC path load

crates/rds-desktop/src/session.rs

@@ -843,6 +843,10 @@ pub async fn serve_desktop_with(
                         delayed_bytes,
                         failed_frames,
                         path_rtt_ms = ?path.map(|p| p.rtt.as_millis()),
+                        path_id = ?path.map(|p| p.path_id),
+                        path_cwnd_bytes = ?path.map(|p| p.cwnd),
+                        path_sent_bytes = ?path.map(|p| p.sent_bytes),
+                        path_received_bytes = ?path.map(|p| p.recv_bytes),
                         path_via_relay = ?path.map(|p| p.via_relay),
                         path_sent = ?path.map(|p| p.sent),
                         path_lost = ?path.map(|p| p.lost),
@@ -878,6 +882,10 @@ pub async fn serve_desktop_with(
                         obsolete_delivery = feedback.obsolete.load(Ordering::Relaxed),
                         last_ack_ms = feedback.last_ack_ms.load(Ordering::Relaxed),
                         path_rtt_ms = ?path.map(|p| p.rtt.as_millis()),
+                        path_id = ?path.map(|p| p.path_id),
+                        path_cwnd_bytes = ?path.map(|p| p.cwnd),
+                        path_sent_bytes = ?path.map(|p| p.sent_bytes),
+                        path_received_bytes = ?path.map(|p| p.recv_bytes),
                         path_via_relay = ?path.map(|p| p.via_relay),
                         path_sent = ?path.map(|p| p.sent),
                         path_lost = ?path.map(|p| p.lost),
@@ -1810,7 +1818,7 @@ async fn send_frame_inner(
                 _ = tokio::time::sleep(delay_budget) => {
                     feedback.mark_delayed(payload_bytes);
                     late = Some(LateReceipt::new(feedback.clone()));
-                    tracing::warn!(frame_seq=seq,payload_bytes,delay_budget_ms=delay_budget.as_millis(),"desktop frame delivery delayed");
+                    tracing::warn!(frame_seq=seq,keyframe,payload_bytes,delay_budget_ms=delay_budget.as_millis(),"desktop frame delivery delayed");
                     receipt.await
                 }
             }
@@ -1820,6 +1828,19 @@ async fn send_frame_inner(
             Ok(Ok(None)) => {
                 sending.finished = true;
                 feedback.acknowledged(payload_bytes, transfer_started.elapsed(), delay_budget);
+                if late.is_some() {
+                    // Complete the soft-delay record at ordinary diagnostic
+                    // verbosity; the initial crossing alone hid its duration.
+                    tracing::info!(
+                        frame_seq = seq,
+                        keyframe,
+                        payload_bytes,
+                        enqueue_ms = started.duration_since(transfer_started).as_millis(),
+                        ack_ms = started.elapsed().as_millis(),
+                        transfer_ms = transfer_started.elapsed().as_millis(),
+                        "desktop delayed frame transport acknowledged"
+                    );
+                }
                 tracing::trace!(frame_seq=seq,payload_bytes,ack_ms=started.elapsed().as_millis(),"desktop frame transport acknowledged");
                 FrameReceipt::Delivered
             }
@@ -1832,7 +1853,7 @@ async fn send_frame_inner(
             result => {
                 feedback.failed.fetch_add(1, Ordering::Relaxed);
                 request_frame_repair(&latest_key_seq, &idr, seq);
-                tracing::warn!(frame_seq=seq,payload_bytes,ack_ms=started.elapsed().as_millis(),outcome=?result,"desktop frame delivery unconfirmed");
+                tracing::warn!(frame_seq=seq,keyframe,payload_bytes,ack_ms=started.elapsed().as_millis(),outcome=?result,"desktop frame delivery unconfirmed");
                 FrameReceipt::Failed
             }
         };

docs/native-viewer.md

@@ -507,3 +507,14 @@ repair a second time. A newer produced key suppresses another request for an
 older frame, including reference-admission rejection while that key is queued.
 Current failures and unknown worker termination still require repair. This
 correlation does not treat a produced picture as successful delivery.
+
+Serving-side delivery health and bitrate-reduction records include selected
+`path_id`, instantaneous `path_cwnd_bytes` and cumulative sent/received UDP bytes.
+Compare byte deltas only within the same path id; these counters include other
+services on that connection and do not measure media throughput alone. A soft
+delayed-frame warning now has a matching ordinary-level completion record with
+sequence, keyframe flag, payload length, `enqueue_ms`, `ack_ms` and `transfer_ms`.
+Enqueue spans stream opening/writes and scheduling of the receipt worker; ACK
+spans that worker's transport receipt wait. Neither is an application input ACK
+or a physical presentation measurement. Timely frame completions remain trace
+level. The diagnostic addition changes no pacing, admission or deadlines.

docs/reports/rds-delivery-observation-20261003.md

@@ -0,0 +1,29 @@
+# Delivery observation follow-up — 2026-10-03
+
+W6.6/W6.7 and observability follow-up, without a completed stability gate.
+Installed qualification of the payload-aware controller still found a multi-
+second media pause with fresh control echoes. Receiver metadata localized one
+independent picture to a slow body read, and serving metadata showed the
+keyframe receipt barrier holding further capture. The precise transport cause
+was not established; no endpoint identities, private runtime data or payloads
+are part of this public receipt.
+
+Ordinary health and reduction records now include the selected path id,
+instantaneous congestion-window bytes and cumulative UDP sent/received bytes.
+A path change invalidates cross-path counter subtraction. UDP counters cover
+the entire connection's selected path, including other services; they are not
+an isolated media-goodput or available-capacity estimate.
+
+Successful receipts that previously crossed their soft deadline now produce
+an info completion record, pairing the initial warning's sequence with its
+keyframe flag, payload size and enqueue/receipt/total duration. Existing timely
+completion trace records, independent five-second production health and receiver
+slow-body logs remain. This allows diagnostics to distinguish a frozen producer,
+waiting keyframe, slow enqueue and slow transport receipt without requiring
+per-frame verbose tracing. No keys, input values, clipboard data or pixels are
+logged, and no wire, deadline, recovery or scheduling behavior changes.
+
+Verification on macOS arm64: fmt, strict workspace all-target desktop-feature
+clippy and all 45 session tests passed. Native Linux/macOS CI and an installed
+receipt remain separate. This increment adds diagnostic fields and does not
+assert a network or click-to-visible latency improvement.