Daemon hangs when disabling monitor

[ettancos]

Hi
I found an issue when I was trying to disable the laptop monitor on multi-monitor setup. The behavior was strange because swww-daemon was just hanging, no response for Ctrl+c, only kill -9 worked. Then I narrowed it down because when I enabled the display it got unstuck, that made me curious so I looked into it more.

In the end it looks like reading the payload is blocking when there is no payload (size = 0). In this case its the wl_output.done event.

I confirmed this by moving that section to an if size > 0 block and that seemed to have resolved it, not sure what is the rusty way to add that guard here. I might be missing something, don't know the wire level too much.

[LGFae]

Oh! Nice catch. That extra if statement seems to be exactly what we need. Do you want to make a PR with the change?