subscription over websocket

[jangko]

before we implement subscription over websocket there are some issue need to be addressed first:

• [ ] the same subscription may need to be served to many clients connected to the server, how the state or the subscription context should be managed or shared or split among connections?
• [ ] should it share the same schema instance with query/mutation or using it's own copy or slices of the schema?
• [ ] is there any standardization or specification of protocol over websocket?
• [ ] can we use https://github.com/apollographql/subscriptions-transport-ws/blob/master/PROTOCOL.md