RPC callback lacks type_url

[quanterion]

In RPCImpl callback I can access requestData. That is UInt8Array.
I want to write the request message to Any field of generic Request object

message RpcRequest {
	google.protobuf.Any data = 2;
	int32 resultId = 3;
}

To assign data field (typed as Any) I need type_url since Any declared this way:

    ```
   interface IAny {
        /** Any type_url */
        type_url?: (string|null);

        /** Any value */
        value?: (Uint8Array|null);
    }

Can you add type_url to RPCImpl callback?

[quanterion]

After searching I think #857 would partially problem