Add UDP support to dart:io

sdk/lib/_internal/lib/io_patch.dart

Index: sdk/lib/_internal/lib/io_patch.dart
diff --git a/sdk/lib/_internal/lib/io_patch.dart b/sdk/lib/_internal/lib/io_patch.dart
index bc87e41b546bb272d7ea6d1e60622ed8ce213732..426992b6805494905a3d21dd172ac7768c674e53 100644
--- a/sdk/lib/_internal/lib/io_patch.dart
+++ b/sdk/lib/_internal/lib/io_patch.dart
@@ -293,6 +293,13 @@ patch class SecureSocket {
   }
 }
 
+patch class RawDatagramSocket {
+  patch static Future<RawDatagramSocket> bind(
+      host, int port, {bool reuseAddress: true}) {
+    throw new UnsupportedError("RawDatagramSocket.bind");
+  }
+}
+
 patch class _SecureFilter {
   patch factory _SecureFilter() {
     throw new UnsupportedError("_SecureFilter._SecureFilter");