Exception when passing BusState to RemoteBus

[cody82]

On initialization of RemoteBus I get an exception on this line because it can not convert BusState to json:

python-can-remote/can_remote/protocol.py

Line 66 in 5e76930

self._ws.send(json.dumps({"type": event_type, "payload": payload}))

BusState is defined here:
https://github.com/hardbyte/python-can/blob/develop/can/bus.py#L22

How could that be fixed? Other Bus implementations allow this parameter. (Like https://github.com/hardbyte/python-can/blob/develop/can/interfaces/pcan/pcan.py#L117)