Implements a simple polling interface for file descriptors that don't work with select() - this is pretty much only useful on Windows.
| Variable | MIN_TIMEOUT | Undocumented |
| Variable | MAX_TIMEOUT | Undocumented |
| Variable | FULL_BUFFER_SIZE | Undocumented |
| Class | _PollableResource | Undocumented |
| Class | _PollingTimer | Undocumented |
| Class | _PollableReadPipe | Undocumented |
| Class | _PollableWritePipe | No class docstring; 0/7 instance variables, 4/10 methods documented |