Support other Serializers for SignalR Protocol so we can support Trimming/AOT

[SerratedSharp]

It looks like MessagePack does not support trimming/AOT. MemoryPack does work with these when types have proper annotations, and is a very fast sterilizer which goes great with high performance WebSockets, but as far as I understand it's not possible to specify a custom serializer for SignalR. It might kill two birds with one stone to define an interface that SignalR needs from a serializer so that we can map other serializers to it, and in turn have a high performance serializer over WebSockets which also support tirmming/AOT.

[BrennanConroy]

There is an interface, IHubProtocol. Just add it to the service provider and configure your client(s) to use that protocol as well. e.g. https://source.dot.net/#Microsoft.AspNetCore.SignalR.Protocols.Json/JsonProtocolDependencyInjectionExtensions.cs,38

I would recommend not using MemoryPack though, it is not a safe serializer.

[SerratedSharp]

Thanks, I took another discussion at face value that said it was tightly coupled to JSON and MessagePack. I'll take a look at this!

What is unsafe about MemoryPack? Is the concern arbitrary deserialization of unsafe types? You must annotate which types are serializable, so I assumed it is constrained to only those types. I'll have to see how it works on the deserialization side to see if it also requires that annotation.