Add error handling to socket streams

runtime/bin/output_stream.dart

Index: runtime/bin/output_stream.dart
diff --git a/runtime/bin/output_stream.dart b/runtime/bin/output_stream.dart
index 7e5b9ffcb7cd2c20107c328b3ee7a7d2111ecc3f..6583599a7c295b1f7fc53affa7901d3dbcc62517 100644
--- a/runtime/bin/output_stream.dart
+++ b/runtime/bin/output_stream.dart
@@ -82,6 +82,6 @@ interface OutputStream {
    * Sets the handler that gets called when the underlying
    * communication channel gets into some kind of error situation.
    */
-  void set onError(void callback());
+  void set onError(void callback(Exception e));
 }