Observe peer-window recovery after the deferred queue resume

tests/test_etcp_windows.c

@@ -590,7 +590,12 @@ static void peer_window_queries(void) {
     CHECK(queue_data_put(conn->input_queue, &fragment->ll) == 0 && conn->ack_window_timer);
     wait_sends(1); CHECK(last_sent_request && !last_sent_payload && last_sent_link);
     receive_till(last_sent_link, MAX_INFLIGHT_SIZE, 0);
-    CHECK(!conn->ack_window_timer && !conn->input_queue->count && conn->input_send_q->count == 1);
+    uasync_drain_immediate(ua); // queue_resume_callback выполняется через call_soon
+    DEBUG_INFO(DEBUG_CATEGORY_DEBUG, "Peer window reply: next=%u till=%u query_timer=%d input=%d send=%d callback_pending=%d",
+        conn->next_tx_id, conn->rx_ack_till, !!conn->ack_window_timer, conn->input_queue->count,
+        conn->input_send_q->count, !!conn->input_queue->callback_suspended);
+    CHECK(!conn->ack_window_timer && !conn->input_queue->count && conn->unacked_bytes == 1);
+    CHECK(conn->input_send_q->count + conn->input_wait_ack->count == 1);
     teardown();
 }