Questions about protobuf protocols

I'm implementing the missing protobuf protocols and i think that the documentation [here ](https://learn.microsoft.com/en-us/azure/azure-web-pubsub/reference-protobuf-reliable-webpubsub-subprotocol#requests) is incorrect as it should be:

> oneof message {
SendToGroupMessage send_to_group_message = 1;
EventMessage event_message = 5;
JoinGroupMessage join_group_message = 6;
LeaveGroupMessage leave_group_message = 7;
SequenceAckMessage sequence_ack_message = 8;
}

Is also not clear to me what is the role of the WriteMessage override since it is never called.
Plan to contribute with a PR once implementation will be completed.

Compare the missing protobuf protocol definitions with the Azure Web PubSub reliable Web PubSub subprotocol request documentation linked in the issue. Then trace the WriteMessage override to understand why it is not called. Done means the missing protocols are implemented, the documentation discrepancy is resolved or confirmed, and a pull request is ready.

Written by the indexing model from the issue text.