public MessageDescriptor()
{
Name = string.Empty;
Fields = new List<FieldDescriptor>();
Extensions = new List<FieldDescriptor>();
NestedTypes = new List<MessageDescriptor>();
EnumTypes = new List<EnumDescriptor>();
ExtensionRanges = new List<ExtensionRange>();
OneofDecl = new List<OneofDescriptor>();
Options = null;
}