help. What is the solution similar to protobuf.wrappers in rust-protobuf?

[ape-casear]

background:
I have a message A that is used everywhere.

message A {
      u32 define_type = 1;
      bytes sub_message = 2;
}

and there is a map that maintains the relationship between id and sub_message.
problem:
when I use parse_from_bytes to get a message that contains message A. I want to get the real message behind the bytes sub_message.

The place where MessageA is used looks like this

// normal
message B {
      u32 foo = 1;
      A  a = 2;
}
// nested
message C {
      u32 foo = 1;
      B b = 2;
}

In js. protobuf.wrappers solves my problem.

const protobuf = require('protobufjs')
protobuf.wrappers['.pkg.A'] = {
    toObject(message, options) {
        const originOutput = this.toObject(message, options)
        if (map.has(originOutput.define_type)) {
            const message_type = map.get(originOutput.define_type;
            originOutput.sub_message = message_type.decode(Buffer.from(originOutput.sub_message, 'base64'))
        }
        return originOutput
    },
    fromObject(object) {
        return this.fromObject(object)
    },
}

What is the solution similar to protobuf.wrappers in rust-protobuf?