Protobuf support is missing with client & server SDKs

There is a [link ](https://learn.microsoft.com/en-us/azure/azure-web-pubsub/reference-protobuf-webpubsub-subprotocol#publish-messages) about using protobuf but it does not tell how to send and receive these proto messages or data in any language. atleast C#, javascript should have support.

Start with the linked Azure Web PubSub protobuf subprotocol reference and inspect the client and server SDK areas for C# and JavaScript support. Define the required send and receive examples for both SDKs, then verify that the documentation or implementation covers protobuf messages end to end.

Written by the indexing model from the issue text.