Go中任意类型消息的自定义protobuf选项

我的GRPC服务定义如下：

message SendEventRequest {
  string producer = 1;
  google.protobuf.Any event = 2;
}

message SendEventResponse {
  string event_name = 1;
  string status = 2;
}

service EventService {
  rpc Send(SendEventRequest) returns (SendEventResponse);
}

我还定义了一个自定义消息选项：

extend google.protobuf.MessageOptions {
  // event_name is the unique name of the event sent by the clients
  string event_name = 50000;
}

event_name

message SomeCustomEvent {
  option (mypackage.event_name) = "some_custom_event";

  string data = 1;
  ...
}

proto.Message

_, md := descriptor.MessageDescriptorProto(SomeCustomEvent)
mOpts := md.GetOptions()
eventName := proto.GetExtension(mOpts, mypackage.E_EventName)

github.com/golang/protobuf/ptypes/any.Anyevent_nameprotoregistry.MessageTypeResolver