Don't supply host names for the fixed internet addresses

sdk/lib/io/socket.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.io;
 
 
 /**
  * [InternetAddressType] is the type an [InternetAddress]. Currently,
  * IP version 4 (IPv4) and IP version 6 (IPv6) are supported.
@@ skipping 59 matching lines @@
    * all adapters IP addresses using IP version 6 (IPv6).
    */
   external static InternetAddress get ANY_IP_V6;
 
   /**
    * The [type] of the [InternetAddress] specified what IP protocol.
    */
   InternetAddressType type;
 
   /**
-   * The resolved address of the host.
+   * The numeric address of the host. For IPv4 addresses this is using
+   * the dotted-decimal notation. For IPv6 it is using the
+   * hexadecimal representation.
    */
   String get address;
 
   /**
-   * The host used to lookup the address.
+   * The host used to lookup the address. If there is no host
+   * associated with the address this returns the numeric address.
    */
   String get host;
 
   /**
    * Returns true if the [InternetAddress] is a loopback address.
    */
   bool get isLoopback;
 
   /**
    * Returns true if the [InternetAddress]s scope is a link-local.
@@ skipping 404 matching lines @@
     sb.write("SocketException");
     if (!message.isEmpty) {
       sb.write(": $message");
       if (osError != null) {
         sb.write(" ($osError)");
       }
     } else if (osError != null) {
       sb.write(": $osError");
     }
     if (address != null) {
-      if (address.host.isNotEmpty) {
-        sb.write(", address = ${address.host}");
-      } else {
-        sb.write(", address = ${address.address}");
-      }
+      sb.write(", address = ${address.host}");
     }
     if (port != null) {
       sb.write(", port = $port");
     }
     return sb.toString();
   }
 }