If Jackson serialization fails, a checked exception is thrown in WebsocketGraphQLWSProtocolHandler, but the library code written in Java is written to only catch runtime exceptions; switch to throwing a runtime exception so that the appropriate error handler is called.
If Jackson serialization fails, a checked exception is thrown in WebsocketGraphQLWSProtocolHandler, but the library code written in Java is written to only catch runtime exceptions; switch to throwing a runtime exception so that the appropriate error handler is called.
Fixes #1629