Support for "old" servers

[sruehl]

I have a server which responds with the old format (https://github.com/SignalR/SignalR) for negotation which looks like what can be found here: https://github.com/alexjorgef/signalr/blob/main/client.go#L14

I wonder what is necessary to make this lib (https://github.com/philippseith/signalr) support older servers too. This is the root case for https://github.com/philippseith/signalr/issues/193

[philippseith]

• I could not find any written spec for the ASP.NET SignalR 1.x negotiation process.
• From the source you linked, one can see that the negotiate response looks similar, but has some unclear properties. What are the values of protocolVersion? How decide to use WebSockets seems clear, but how to differentiate between SSE and LongPolling?
• If you look at https://github.com/alexjorgef/signalr/blob/main/client.go#L174 even the messages seem to be serialized in a different way.

I don't guess this will work.