Add InternetAddress:rawAddress, to return the raw address as a list of bytes.

sdk/lib/io/socket.dart

Index: sdk/lib/io/socket.dart
diff --git a/sdk/lib/io/socket.dart b/sdk/lib/io/socket.dart
index 932fb97a319b309439d7c379a998c2fa416617bf..f8d854382b3b41b8d3308301a46fb2a193047c16 100644
--- a/sdk/lib/io/socket.dart
+++ b/sdk/lib/io/socket.dart
@@ -90,6 +90,13 @@ abstract class InternetAddress {
   String get host;
 
   /**
+   * Get the raw address of this [InternetAddress]. The result is either a
+   * 4 or 16 byte long list. The returned list is a copy, making it possible
+   * to change the list without modifying the [InternetAddress].
+   */
+  List<int> get rawAddress;
+
+  /**
    * Returns true if the [InternetAddress] is a loopback address.
    */
   bool get isLoopback;