Function SetValue

libapp2sys/prebuilt/include/google/protobuf/map.h:433–435

    return (FieldDescriptor::CppType)type_;
  }
  void SetValue(const void* val) {
    data_ = const_cast<void*>(val);
  }
  void CopyFrom(const MapValueRef& other) {
    type_ = other.type_;
    data_ = other.data_;