Endpoint handles a HTTP request and upgrades it, giving the user a channel to receive messages down and a reply channel to send messages to the websocket.

NewBroadcast, creating a new map and new counter for messages and set up the server that handles new subscriptions.

Context to use when logging.

ContextBroadcast used to identify the broadcast server in logging.

DeadlinePong to send after a ping request in the control message.