SSEChat never closes

[thelabcat]

AFAIK the SSEClient object is supposed to raise StopIteration when chat closes, which I'd think should happen when the livestream ends, but this never occurs, or at least not in my tests. Getting the next chat message will just hang forever after the stream is over.

[thelabcat]

Added Band-aid patch for this in 6e9f4a7, SSE read timeout now declares the stream as ended.

[thelabcat]

Right now, the chat is eventually closing if there's no activity for a long time. Not sure if this is an actual close or a read timeout.

[thelabcat]

Maybe we should have a normal timeout, but attempt reconnect after timeout and see what happens.