Handling multiple types of messages in loop ?

[glennpierce]

I have the following proto interface

syntax = "proto3";

package bmos;

message BmosPointsDataFrameRequest {
  string site_group_namespace = 1;
  repeated int32 site_group_ids = 2;
  repeated int32 point_ids = 3;
}

message BmosSetStoreRequest {
  string data = 1;
}

message BmosGetStoreRequest {
}

message BmosResponse {
  bytes dataframe = 1;
}

I am having a nightmare handling it though.

I have a event handler like

loop {
        match responder.recv(&mut msg, 0) {
            Ok(_) => {
                // Handle received message
     
            }
            Err(e) => {
                // Handle receive error
                println!("Error receiving message: {}", e);
               
                continue; 
            }
        }
    }

I could handle when I knew the request in advance like

let request = match bmos::BmosPointsDataFrameRequest::decode(&*msg) {
                        Ok(request) => request,
                        Err(e) => {
                            // Error decoding the request
                            log::error!("Failed to decode Protocol Buffers message: {}", e);
                            continue;
                        }
                    };

but how can handle any type of message in the loop dynamically ?
Maybe put a required string as the first entry of each message and match that in the byte stream ?