Add transmission timing details

lib/utils/raw_route_probe.dart

@@ -0,0 +1,87 @@
+import 'dart:typed_data';
+
+class RawRouteProbeRequest {
+  static const int _binaryMagic = 0x70; // 'p'
+
+  final int nonce;
+  final String requesterKey6;
+
+  const RawRouteProbeRequest({
+    required this.nonce,
+    required this.requesterKey6,
+  });
+
+  static RawRouteProbeRequest? tryParseBinary(Uint8List payload) {
+    if (payload.length != 11 || payload[0] != _binaryMagic) return null;
+    try {
+      final nonce =
+          (payload[1] << 24) |
+          (payload[2] << 16) |
+          (payload[3] << 8) |
+          payload[4];
+      final requesterKey6 = payload
+          .sublist(5, 11)
+          .map((b) => b.toRadixString(16).padLeft(2, '0'))
+          .join()
+          .toLowerCase();
+      return RawRouteProbeRequest(nonce: nonce, requesterKey6: requesterKey6);
+    } catch (_) {
+      return null;
+    }
+  }
+
+  Uint8List encodeBinary() {
+    if (!RegExp(r'^[0-9a-fA-F]{12}$').hasMatch(requesterKey6)) {
+      throw ArgumentError.value(
+        requesterKey6,
+        'requesterKey6',
+        'Expected 12 hex chars',
+      );
+    }
+    final out = Uint8List(11);
+    out[0] = _binaryMagic;
+    out[1] = (nonce >> 24) & 0xFF;
+    out[2] = (nonce >> 16) & 0xFF;
+    out[3] = (nonce >> 8) & 0xFF;
+    out[4] = nonce & 0xFF;
+    for (var i = 0; i < 6; i++) {
+      out[5 + i] = int.parse(
+        requesterKey6.substring(i * 2, i * 2 + 2),
+        radix: 16,
+      );
+    }
+    return out;
+  }
+}
+
+class RawRouteProbeAck {
+  static const int _binaryMagic = 0x71; // 'q'
+
+  final int nonce;
+
+  const RawRouteProbeAck({required this.nonce});
+
+  static RawRouteProbeAck? tryParseBinary(Uint8List payload) {
+    if (payload.length != 5 || payload[0] != _binaryMagic) return null;
+    try {
+      final nonce =
+          (payload[1] << 24) |
+          (payload[2] << 16) |
+          (payload[3] << 8) |
+          payload[4];
+      return RawRouteProbeAck(nonce: nonce);
+    } catch (_) {
+      return null;
+    }
+  }
+
+  Uint8List encodeBinary() {
+    final out = Uint8List(5);
+    out[0] = _binaryMagic;
+    out[1] = (nonce >> 24) & 0xFF;
+    out[2] = (nonce >> 16) & 0xFF;
+    out[3] = (nonce >> 8) & 0xFF;
+    out[4] = nonce & 0xFF;
+    return out;
+  }
+}