The best pattern on this issue is to make sure, in case WebSocket connection is closed, to clean up all user ids and call ids of this RCC connection.

You can send a message with {"mt":"KeepAlive"} from time to time, to make sure the TCP connection accepts data. Otherwise it will be closed and you know that all ids are invalidated at the moment.

I would not rely on the correct order of the messages here. Instead, you could send the following UserInitialize first, when result for previous one was delivered.

We could discuss it in the SDK Dialog, in case the questions are still open.