For full background info, see also python-jsonschema/jsonschema#548

The jsonschema library is already in typeshed, but is going to introduce a new Protocol class (assuming I can sort out what should happen to add it).
This is made tricky by the fact that jsonschema does not have PEP561 metadata, but we want to add a Protocol which is explicitly meant for type-checking usages.

I'm not clear on what the correct order of operations is here. Should we get the protocol included in jsonschema, and then add it to typeshed, acknowledging that the protocol won't be that useful until we do?
I'm happy to work up the typeshed PR, but I'd like to do so with the assurance that it will be merged and that the types for jsonschema won't diverge from the library itself for too long.