Block until ready for writing

[multimeric]

Further to discussion here: tuomasjjrasanen/python-uinput#6 (comment), we have noticed that attempting to use suinput_create, and then immediately suinput_emit will not work, likely because suinput_create isn't blocking until it's ready. It returns immediately.

Might this be because we're opening the uinput device with O_NONBLOCK? Alternatively, I notice in the uinput kernel examples, they also use a sleep(1), but say that "This pause is only needed in our example code". Any idea how we can have libsuinput do this for us?

/*
* On UI_DEV_CREATE the kernel will create the device node for this
* device. We are inserting a pause here so that userspace has time
* to detect, initialize the new device, and can start listening to
* the event, otherwise it will not notice the event we are about
* to send. This pause is only needed in our example code!
*/