Start better error reporting for sockets

tests/standalone/src/io/EchoServerStreamTest.dart

 // Copyright (c) 2012, 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.
 //
 // Echo server test program to test socket streams.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
@@ skipping 17 matching lines @@
       _buffer[i] = FIRSTCHAR + i;
     }
     new EchoServer().spawn().then((SendPort port) {
       _sendPort = port;
       start();
     });
   }
 
   void sendData() {
 
-    void errorHandler() {
-      Expect.fail("Socket error");
+    void errorHandler(Exception e) {
+      Expect.fail("Socket error $e");
     }
 
     void connectHandler() {
 
       SocketOutputStream stream = _socket.outputStream;
 
       void dataSent() {
         InputStream inputStream = _socket.inputStream;
         int offset = 0;
         List<int> data;
@@ skipping 104 matching lines @@
         for (int i = 0; i < offset; i++) {
           Expect.equals(EchoServerGame.FIRSTCHAR + i, buffer[i]);
         }
         if (offset == MSGSIZE) {
           outputStream.write(buffer);
           outputStream.close();
         }
       }
     }
 
-    void errorHandler() {
-      Expect.fail("Socket error");
+    void errorHandler(Exception e) {
+      Expect.fail("Socket error $e");
     }
 
     inputStream = connection.inputStream;
     inputStream.onData = dataReceived;
     connection.onError = errorHandler;
   }
 }
 
 main() {
   EchoServerGame echoServerGame = new EchoServerGame.start();
 }