Update C# bindings to 1.4.0 API

src/bindings/csharp/RouteInfo.cs

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c)2013-2021 ZeroTier, Inc.
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file in the project's root directory.
+ *
+ * Change Date: 2026-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2.0 of the Apache License.
+ */
+/****/
+
+using System.Net;
+
+using ZeroTier;
+
+namespace ZeroTier.Core
+{
+    public class RouteInfo {
+        public RouteInfo(IPAddress target, IPAddress via, ushort flags, ushort metric)
+        {
+            _target = target;
+            _via = via;
+            _flags = flags;
+            _metric = metric;
+        }
+
+        public IPAddress _target;
+        public IPAddress _via;
+        public ushort _flags;
+        public ushort _metric;
+
+        public IPAddress Target
+        {
+            get {
+                return _target;
+            }
+        }
+        public IPAddress Via
+        {
+            get {
+                return _via;
+            }
+        }
+        public ushort Flags
+        {
+            get {
+                return _flags;
+            }
+        }
+        public ushort Metric
+        {
+            get {
+                return _metric;
+            }
+        }
+    }
+}