The Twit docs [specifically says](https://github.com/ttezel/twit#using-the-streaming-api) that the `stream` function returns an `EventEmitter`. It also says that the `EventEmitter` has [two methods - `start()` and `stop()`](https://github.com/ttezel/twit#streamstop) to start and stop the Twitter stream.
The return type was incorrectly specified as a `NodeJS.ReadableStream`. This fixes that.