WebSocket support #161
Description
Official AWS docs seem pretty thin on the ground so far. This is the best overview:
https://serverless.com/blog/api-gateway-websockets-support/
The API should probably look something like this:
https://javalin.io/documentation#websockets
websocket("/websocket/:path") {
onConnect { session -> ... }
onMessage { session, message -> ... }
onClose { session, statusCode, reason -> ... }
onError { session, throwable -> ... }
}