WindowsApiEmitter made easier to subclass.

[petrblahos]

queue_events now does not call read_events directly. The call
was put into a member function _read_events instead, to make
it easier to replace the read_events functionality while keeping
the rest of the class going.

I need to make the WindowsApiObserver reconnect on the network
failure. I achieve it by catching certain errors in get_directory_handle
and read_events, but with the way the code has been organized
I had to "copy/paste" whole read_directory_changes file. If I take the
read_events out of the queue_events, I can just override on_thread_start,
on_thread_stop and the new _read_events to achieve this.

[xiaogigagagigigo]

I would like to know, how you solved that issue: I'm getting WindowsError: [Error 64] in read_directory_changes, when network-drive is sometimes not reachable. Would you be so kind to explain, how you managed to reconnect watchdog surveillance, if device is connected again?

[petrblahos]

https://gist.github.com/petrblahos/7a5171d0f42297db2676c968c8034110

This works against current watchdog (without my PR applied). That's why I had to copy the whole winobserver from watchdog and add a thing here or there. With the patch applied, all things would happen in read_events function.

[BoboTiG]

@danilobellini I am OK to merge this one, WDYT?

[BoboTiG]

Thank you @petrblahos :)