Process service events as microtasks.

runtime/observatory/lib/service_common.dart

Index: runtime/observatory/lib/service_common.dart
diff --git a/runtime/observatory/lib/service_common.dart b/runtime/observatory/lib/service_common.dart
index 0faa080bb8cc00abe77b3eca452d9434894e26a1..cde76a2c1fdba8a3278c2cff58e8def1712eff70 100644
--- a/runtime/observatory/lib/service_common.dart
+++ b/runtime/observatory/lib/service_common.dart
@@ -209,7 +209,7 @@ abstract class CommonWebSocketVM extends VM {
       }
       var event = map['params']['event'];
       var streamId = map['params']['streamId'];
-      postServiceEvent(streamId, event, data);
+      scheduleMicrotask(() { postServiceEvent(streamId, event, data); });
     });
   }
 
@@ -222,7 +222,7 @@ abstract class CommonWebSocketVM extends VM {
     if (map['method'] == 'streamNotify') {
       var event = map['params']['event'];
       var streamId = map['params']['streamId'];
-      postServiceEvent(streamId, event, null);
+      scheduleMicrotask(() { postServiceEvent(streamId, event, null); });
       return;
     }