Protocol Buffer runtime library and 'protoc' plugin

lib/protobuf/runtime/Message.dart

Index: lib/protobuf/runtime/Message.dart
diff --git a/lib/protobuf/runtime/Message.dart b/lib/protobuf/runtime/Message.dart
new file mode 100644
index 0000000000000000000000000000000000000000..400dc4a26ef68b00afbfa4e659f8b145523abb61
--- /dev/null
+++ b/lib/protobuf/runtime/Message.dart
@@ -0,0 +1,12 @@
+// Copyright (c) 2011, 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.
+
+interface Message {
+  int getSerializedSize();
+  bool hasRequiredFields();
+  bool isInitialized();
+  void writeToCodedBufferWriter(CodedBufferWriter output);
+  String writeToJson();
+  void _findInvalidFields(List<String> invalidFields, String prefix);
+}