Support for starting, monitoring, and restarting child process.
| Class | DummyTransport | Undocumented |
| Class | LineLogger | Undocumented |
| Class | LoggingProtocol | Undocumented |
| Class | ProcessMonitor | ProcessMonitor runs processes, monitors their progress, and restarts them when they die. |
| Class | _Process | The parameters of a process to be restarted. |