feat(quic): replace probe UDP data plane with QUIC datagrams

backend/shared/MoShiro.Measurement/Blocks/Echo.cs

@@ -11,7 +11,7 @@ namespace MoShiro.Measurement;
 internal sealed class EchoRows
 {
     /// <summary>UDP：没有在这段时间内回来的包就是丢了。</summary>
-    public const long UdpGraceUs = 2_000_000;
+    public const long DatagramGraceUs = 2_000_000;
 
     /// <summary>
     /// TCP 不会丢包，只会延迟（重传、队头阻塞）：一次几秒的中断之后，积压的回显会陆续回来，RTT 就是那几秒。
@@ -65,26 +65,27 @@ internal sealed class EchoRows
 /// <summary>
 /// UDP 回显，拨号方（Probe）：按声明的速率发包，t1 在发出时记录，回复到达时回填 t4。回复丢失的行 t4 缺失（Agent 一侧再补 t2/t3）。
 /// </summary>
-public sealed class UdpEchoDialer : BlockBase
+public sealed class DatagramEchoDialer : BlockBase
 {
     private readonly EchoRows _rows;
 
-    public UdpEchoDialer(BlockEnv env, BlockSpec spec)
+    public DatagramEchoDialer(BlockEnv env, BlockSpec spec)
         : base(env, spec)
     {
-        _rows = new EchoRows(spec.Kind, 16384, EchoRows.UdpGraceUs, settleOnReply: false);
+        _rows = new EchoRows(spec.Kind, 16384, EchoRows.DatagramGraceUs, settleOnReply: false);
     }
 
     public override long Produced => _rows.Count;
 
     public override async Task RunAsync(CancellationToken ct)
     {
-        UdpMux udp = Env.Udp!;
+        QuicDatagramTransport datagrams = Env.Datagrams!;
         DataSession session = Env.Session() ?? throw new BlockFaultException("no data session");
+        await datagrams.WaitUntilConnectedAsync(ct);
         IPEndPoint target = PeerEndpoint(Spec.Port);
         int size = (int)Spec.Int("size");
         byte[] packet = new byte[size];
-        udp.Register(Spec.StreamId, OnPacket);
+        datagrams.Register(Spec.StreamId, OnPacket);
         try
         {
             using var timer = new PeriodicTimer(TimeSpan.FromSeconds(1.0 / Spec.Int("rate_hz")), Env.Time);
@@ -92,8 +93,8 @@ public sealed class UdpEchoDialer : BlockBase
             {
                 long t1 = Env.Clock.NowUs();
                 uint seq = _rows.Add(size, t1);
-                UdpPacket.Write(packet, new UdpHeader(UdpPacketType.EchoRequest, session.SessionId, Spec.StreamId, seq, t1), session.Key);
-                udp.Send(target, packet);
+                MeasurementDatagram.Write(packet, new MeasurementDatagramHeader(MeasurementDatagramType.EchoRequest, session.SessionId, Spec.StreamId, seq, t1), session.Key);
+                datagrams.Send(session, target, packet);
             }
         }
         catch (OperationCanceledException)
@@ -102,7 +103,7 @@ public sealed class UdpEchoDialer : BlockBase
         }
         finally
         {
-            udp.Unregister(Spec.StreamId);
+            datagrams.Unregister(Spec.StreamId);
         }
     }
 
@@ -118,9 +119,9 @@ public sealed class UdpEchoDialer : BlockBase
         return 1;
     }
 
-    private void OnPacket(in UdpDelivery delivery)
+    private void OnPacket(in QuicDatagramDelivery delivery)
     {
-        if (delivery.Header.Type == UdpPacketType.EchoReply)
+        if (delivery.Header.Type == MeasurementDatagramType.EchoReply)
         {
             _rows.Reply(delivery.Header.Seq, delivery.ReceiveUs);
         }
@@ -128,11 +129,11 @@ public sealed class UdpEchoDialer : BlockBase
 }
 
 /// <summary>UDP 回显，监听方（Agent）：校验后立即回复一个等长的包，记录 t2（到达）和 t3（回复发出），按序号留给合并。</summary>
-public sealed class UdpEchoListener : BlockBase
+public sealed class DatagramEchoListener : BlockBase
 {
     private readonly RowStore _records;
 
-    public UdpEchoListener(BlockEnv env, BlockSpec spec)
+    public DatagramEchoListener(BlockEnv env, BlockSpec spec)
         : base(env, spec)
     {
         _records = new RowStore(spec.Kind.FindStream("msg")!, Side.Agent, 32768);
@@ -142,26 +143,26 @@ public sealed class UdpEchoListener : BlockBase
 
     public override async Task RunAsync(CancellationToken ct)
     {
-        Env.Udp!.Register(Spec.StreamId, OnPacket);
+        Env.Datagrams!.Register(Spec.StreamId, OnPacket);
         try
         {
             await WaitUntilCancelledAsync(ct);
         }
         finally
         {
-            Env.Udp.Unregister(Spec.StreamId);
+            Env.Datagrams.Unregister(Spec.StreamId);
         }
     }
 
-    private void OnPacket(in UdpDelivery delivery)
+    private void OnPacket(in QuicDatagramDelivery delivery)
     {
-        if (delivery.Header.Type != UdpPacketType.EchoRequest)
+        if (delivery.Header.Type != MeasurementDatagramType.EchoRequest)
         {
             return; // Data：探活包，只用来保持 NAT 映射和让准入策略学到源地址
         }
 
         long t2 = delivery.ReceiveUs;
-        delivery.ReplyAs(UdpPacketType.EchoReply);
+        delivery.ReplyAs(MeasurementDatagramType.EchoReply);
         Span<long> row = [t2, Env.Clock.NowUs()];
         _records.SetRow(delivery.Header.Seq, row);
     }