Reconnect doesn't work

[Altreus]

Whenever we don't receive a heartbeat we should reconnect.

On the branch refactor-comms I have introduced a WebSocket class, whose job it is to marshal WS messages into the main Connection class. This is supposed to use a migrating Supply so that when a reconnection takes place, the WS class simply emits a new message supply, and the rest of the code should continue.

It appears that it:

• Fails to receive a heartbeat
• Destroys the current WS
• Creates a new WS, with the correct sequence number
• Connects to Discord and sends the resume payload
• Receives nothing from it

I am unable to prove that this is not my fault - mostly because it probably is. It's hard to believe that Discord is doing it wrong. But I cannot ascertain what part of the mechanism is failing.

It would be good to have #40 going, so that we can use a fake Discord to force the disconnection.