Generating golang structs from protobufs without the extra hidden fields

Consider the following message:

message Moo {
  uint64 generation = 1;
  string title = 2;
  bytes payload = 3;
  repeated string flags = 4;
}

In addition to the type Moo struct that protoc generates, which contains extra fields (state, sizeCache, unknownFields in the code I just generated), I also need to generate a type without the extra fields, something like

type MooLight struct {
    Generation uint64
    Title      string
    Payload    []byte
    Flags      []string
}

(whether the tags are there make no difference to me, I've omitted them here for clarity).

I know I can always write some code that takes the generated moo.pb.go file, and starting with var File_moo_proto protoreflect.FileDescriptor generate the "light" structs, but it would be better to let the protocol compiler do it. Any suggestions or advice? I tried looking at the go protoc plugin, and it's a tremendous amount of code.