Better Monitoring

If you try working with our current LineMonitor implementation you will find it has some disadvantages.

1. There is no way to stop monitoring.

2. In particular, if the underlying subprocess crashes, the monitor will just block for ever - it is blocked trying to .readline() - but the line will never come.

Furthermore, we originally wanted the ability to have more than one callback.

Let’s improve our LineMonitor, starting by handling the underlying subprocess a little more carefully.

TBD