具有字典属性的Protobuf-net类

给定下列类，

public static void Test()
{
  var bigDictionary = new Dictionary<string, TestClass>();
  bigDictionary.Add("entry1", new TestClass());
  bigDictionary.Add("entry2", new TestClass());
  bigDictionary.Add("entry3", new TestClass());
  // EDIT: Added these lines
  bigDictionary["entry1"].MyDictionary.Add(1, new SecondTestClass() { MyVar = "hello" });
  bigDictionary["entry1"].MyDictionary.Add(2, new SecondTestClass() { MyVar = "world" });
  bigDictionary["entry2"].MyDictionary.Add(1, new SecondTestClass() { MyVar = "please" });
  bigDictionary["entry2"].MyDictionary.Add(2, new SecondTestClass() { MyVar = "work" });
  using (var file = System.IO.File.Create("test.temp"))
  {
    ProtoBuf.Serializer.Serialize(file, bigDictionary);
  }
  Dictionary<string, TestClass> outDict = null;
  using (var file = System.IO.File.OpenRead("test.temp"))
  {
    outDict = ProtoBuf.Serializer.Deserialize<Dictionary<string, TestClass>>(file);
  }
  // EDIT: You'll notice these asserts fail
  System.Diagnostics.Debug.Assert(outDict["entry1"].MyDictionary.ContainsKey(1));
  System.Diagnostics.Debug.Assert(outDict["entry1"].MyDictionary.ContainsKey(2));
  System.Diagnostics.Debug.Assert(outDict["entry2"].MyDictionary.ContainsKey(1));
  System.Diagnostics.Debug.Assert(outDict["entry2"].MyDictionary.ContainsKey(2));
}
[System.Runtime.Serialization.DataContract]
public class TestClass
{
  public TestClass()
  {
    MyDictionary = new Dictionary<int,SecondTestClass>();
  }
  [System.Runtime.Serialization.DataMember]
  public Dictionary<int, SecondTestClass> MyDictionary { get; set; }
}
[System.Runtime.Serialization.DataContract]
public class SecondTestClass
{
  [System.Runtime.Serialization.DataMember]
  public string MyVar { get; set; }
}

(如何)我可以得到bigDictionary序列化而不抛出以下异常?

"Only data-contract classes (and lists/arrays of such) can be processed (error processing Dictionary`2)"

(我已经尝试标记与DataContract/DataMember ProtoContract/ProtoMember等，但似乎没有工作)

提前感谢您的帮助。

编辑:看来我已经弄明白了。对于上面编辑过的代码，您会注意到断言失败。所以看起来内部字典根本没有被序列化。但是，如果我将datcontract标签更改为Protobuf。ProtoContract(和DataMember到ProtoMember)，它正确地获取内部字典。

是我误用了库还是这是一个bug?