c ++应用程序无法接收来自c＃应用程序的连续消息

TcpClient con = new TcpClient (\"127.0.0.1\", 5432);
            NetworkStream str = con.GetStream ();
Annoucement msg = new Annoucement ();
            msg.typ = Annoucement.msgType.NOWY_GRACZ;

            Serializer.SerializeWithLengthPrefix (str, msg, PrefixStyle.Base128);
            Serializer.SerializeWithLengthPrefix (str, msg, PrefixStyle.Base128);

Connection con = server.accept();

    Annoucement ann = con.receive();
    cout << ann.typ() << endl;

    ann = con.receive();
    cout << ann.typ() << endl;

typ

  Annoucement Connection::receive() throw(EmptySocket) {
    CodedInputStream coded_input(raw_input);
    google::protobuf::uint32 n;
    coded_input.ReadVarint32(&n);
    char *b;
    int m;
    coded_input.GetDirectBufferPointer((const void**)&b, &m);
    Annoucement ann;
    ann.ParseFromArray(b, n);
    return ann;
  }

FileInputStream* raw_input;
 raw_input = new FileInputStream(s);  //s is socket in this example communication